IDT72T40118L4BBI - Integrated Device Technology, Inc.

DECEMBER 2003

DSC-5995/8

IDT and the IDT logo are registered trademarks of Integrated Device Technology, Inc. The TeraSync is a trademark of Integrated Device Technology, Inc.

COMMERCIAL AND INDUSTRIAL TEMPERATURE RANGES

2.5 VOLT HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT CONFIGURATION

16,384 x 40, 32,768 x 40,

65,536 x 40, 131,072 x 40

IDT72T4088, IDT72T4098

IDT72T40108, IDT72T40118

FEATURES

••

•Choose among the following memory organizations:

IDT72T4088 



16,384 x 40

IDT72T4098 



32,768 x 40

IDT72T40108 



65,536 x 40

IDT72T40118 



131,072 x 40

•Up to 250MHz Operation of Clocks

- 4ns read/write cycle time, 3.2ns access time

•Users selectable input port to output port data rates, 500Mb/s

Data Rate

-DDR to DDR

-DDR to SDR

-SDR to DDR

-SDR to SDR

•User selectable HSTL or LVTTL I/Os

•Read Enable & Read Clock Echo outputs aid high speed operation

••

•2.5V LVTTL or 1.8V, 1.5V HSTL Port Selectable Input/Ouput voltage

••

•3.3V Input tolerant

•Mark & Retransmit, resets read pointer to user marked position

•Write Chip Select (WCS) input enables/disables Write

Operations

•Read Chip Select (RCS) synchronous to RCLK

•Programmable Almost-Empty and Almost-Full flags, each flag

FUNCTIONAL BLOCK DIAGRAM

can default to one of four preselected offsets

•Dedicated serial clock input for serial programming of flag offsets

•User selectable input and output port bus sizing

-x40 in to x40 out

-x40 in to x20 out

-x40 in to x10 out

-x20 in to x40 out

-x10 in to x40 out

•Auto power down minimizes standby power consumption

•Master Reset clears entire FIFO

•Partial Reset clears data, but retains programmable settings

•Empty and Full flags signal FIFO status

•Select IDT Standard timing (using EF and FF flags) or First

Word Fall Through timing (using OR and IR flags)

•Output enable puts data outputs into High-Impedance state

•JTAG port, provided for Boundary Scan function

•208 Ball Grid array (PBGA), 17mm x 17mm, 1mm pitch

•Easily expandable in depth and width

•Independent Read and Write Clocks (permit reading and writing

simultaneously)

•High-performance submicron CMOS technology

•Industrial temperature range (-40°°

°°

°C to +85°°

°°

°C) is available

INPUT REGISTER

OUTPUT REGISTER

RAM ARRAY

16,384 x 40,

32,768 x 40

65,536 x 40

131,072 x 40

FLAG

LOGIC

FF/IR

PAF

EF/OR

PAE

READ POINTER

READ

CONTROL

LOGIC

WRITE CONTROL

LOGIC

WRITE POINTER

RESET

LOGIC

WEN WCLK

D0 -Dn (x40, x20, x10)

SREN

MRS

REN

RCLK

Q0 -Qn (x40, x20, x10)

OFFSET REGISTER

PRS

FWFT

SEN

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BUS

CONFIGURATION

FSEL0

FSEL1

MARK

SCLK

RCS

JTAG CONTROL

(BOUNDARY SCAN)

TCK

TMS

TDO

TDI

TRST

RSDR

WCS

ERCLK

EREN

HSTL I/0

CONTROL

Vref

HSTL

WSDR

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

D34

D35

D30

TCK

WCLK

D24

D25

REF

GND

Q3 V

DDQ

GND

D13

Q5D1

GND

D10

D15

FSEL0

D17

Q9 V

DDQ

Q23

Q28

REN

RCLK

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

A1 BALL PAD CORNER

MARK

RCS

DDQ

GND

GND GND

GND

GNDD5

PRS

D29

D26

D18

D19

DDQ

WEN

MRS

WSDR

D27

D23

D37

D32

TDI

TMS

FWFT

WCS

FSEL1

RSDR

D28

D20

D21

D22

D11

Q37

Q39

DDQ

SREN

EREN

ERCLK

Q31

Q34

Q18 Q16 Q14 V

DDQ

Q10Q12

Q6 Q22Q8

D31

TRST

TDO

PAF

FF/IR

D36 D39 D8

D3 V

D6 V

DDQ

GND V

DDQ

GND Q21V

DDQ

Q20V

DDQ

GND V

DDQ

GND Q26V

DDQ

Q27V

DDQ

GND

DDQ

Q13

DDQ

GND

D16 D12

D14 Q19 Q15Q17 Q11 Q38

SEN

PAE

Q30

Q33

Q36

Q29

SCLK

GND

DDQ

GND

DDQ

GND V

DDQ

GND V

DDQ

GND V

DDQ

GND V

DDQ

GND V

DDQ

Q35

Q32

D38

Q24

Q25D33

HSTL GND

D9 GND

5995 drw02

PBGA: 1mm pitch, 17mm x 17mm (BB208-1, order code: BB)

TOP VIEW

PIN CONFIGURATIONS

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

DESCRIPTION

The IDT72T4088/72T4098/72T40108/72T40118 are exceptionally deep,

extremely high speed, CMOS First-In-First-Out (FIFO) memories with the ability

to read and write data on both rising and falling edges of clock. The device has

a flexible x40/x20/x10 Bus-Matching mode and the option to select single or

double data rates for input and output ports. These FIFOs offer several key user

benefits:

•Flexible x40/x20/x10 Bus-Matching on both read and write ports

•Ability to read and write on both rising and falling edges of a clock

•User selectable Single or Double Data Rate of input and output ports

•A user selectable MARK location for retransmit

•User selectable I/O structure for HSTL or LVTTL

•The first word data latency period, from the time the first word is written to

an empty FIFO to the time it can be read, is fixed and short.

•High density offerings up to 5Mbit

•High speed operation of up to 250MHz

Bus-Matching Double Data Rate FIFOs are particularly appropriate for

network, video, telecommunications, data communications and other applica-

tions that require fast data transfer on both rising and falling edges of the clock.

This is a great alternative to increasing data rate without extending the width of

the bus or the speed of the device. They are also effective in applications that

need to buffer large amounts of data and match buses of unequal sizes.

Each FIFO has a data input port (Dn) and a data output port (Qn), both of

which can assume either a 40-bit, 20-bit, or a 10-bit width as determined by the

state of external control pins Input Width (IW), Output Width (OW), and Bus-

Matching (BM) pin during the Master Reset cycle.

The input port is controlled by a Write Clock (WCLK) input and a Write Enable

(WEN) input. Data present on the Dn data inputs can be written into the FIFO

on every rising and falling edge of WCLK when WEN is asserted and Write

Single Data Rate (WSDR) pin held HIGH. Data can be selected to write only

on the rising edges of WCLK if WSDR is asserted. To guarantee functionality

of the device, WEN must be a controlled signal and not tied to ground. This is

important because WEN must be HIGH during the time when the Master Reset

(MRS) pulse is LOW. In addition, the WSDR pin must be tied HIGH or LOW.

It is not a controlled signal and cannot be changed during FIFO operation.

Write operations can be selected for either Single or Double Data Rate mode.

For Single Data Rate operation, writing into the FIFO requires the Write Single

Data Rate (WSDR) pin to be asserted. Data will be written into the FIFO on the

rising edge of WCLK when the Write Enable (WEN) is asserted. For Double

Data Rate operations, writing into the FIFO requires WSDR to be deasserted.

Data will be written into the FIFO on both rising and falling edge of WCLK when

WEN is asserted.

The output port is controlled by a Read Clock (RCLK) input and a Read

Enable (REN) input. Data is read from the FIFO on every rising and falling edge

of RCLK when REN is asserted and Read Single Data Rate (RSDR) pin held

HIGH. Data can be selected to read only on the rising edges of RCLK if RSDR

is asserted. To guarantee functionality of the device, REN must be a controlled

signal and not tied to ground. This is important because REN must be HIGH

during the time when the Master Reset (MRS) pulse is LOW. In addition, the

RSDR pin must be tied HIGH or LOW. It is not a controlled signal and cannot

be changed during FIFO operation.

Read operations can be selected for either Single or Double Data Rate mode.

Similar to the write operations, reading from the FIFO in single data rate requires

the Read Single Data Rate (RSDR) pin to be asserted. Data will be read from

the FIFO on the rising edge of RCLK when the Read Enable (REN) is asserted.

For Double Data Rate operations, reading into the FIFO requires RSDR to be

deasserted. Data will be read out of the FIFO on both rising and falling edge

of RCLK when and REN is asserted.

Both the input and output port can be selected for either 2.5V LVTTL or HSTL

operation. This can be achieved by tying the HSTL signal LOW for LVTTL or

HIGH for HSTL voltage operation. When the read port is setup for HSTL mode,

the Read Chip Select (RCS) input also has the benefit of disabling the read port

inputs, providing additional power savings.

There is the option of selecting different data rates on the input and output ports

of the device. There are a total of four combinations to choose from, Double Data

Rate to Double Data Rate (DDR to DDR), DDR to Single Data Rate (DDR to

SDR), SDR to DDR, and SDR to SDR. The rates can be set up using the WSDR

and RSDR pins. For example, to set up the input to output combination of DDR

to SDR, WSDR will be HIGH and RSDR will be LOW. Read and write operations

are initiated on the rising edge of RCLK and WCLK respectively, never on the

falling edge. If REN or WEN is asserted after a rising edge of clock, no read or

write operations will be possible on the falling edge of that same pulse.

An Output Enable (OE) input is provided for high-impedance control of the

outputs. A read Chip Select (RCS) input is also provided for synchronous

enable/disable of the read port control input, REN. The RCS input is synchro-

nized to the read clock, and also provides high-impedance controls to the Qn

data outputs. When RCS is disabled, REN will be disabled internally and the

data outputs will be in High-Impedance. Unlike the Read Chip Select signal

however, OE is not synchronous to RCLK. Outputs are high-impedanced

shortly after a delay time when the OE transitions from LOW to HIGH.

The Echo Read Enable (EREN) and Echo Read Clock (ERCLK) outputs

are used to provide tighter synchronization between the data being transmitted

from the Qn outputs and the data being received by the input device. These

output signals from the read port are required for high-speed data communi-

cations. Data read from the read port is available on the output bus with respect

to EREN and ERCLK, which is useful when data is being read at high-speed

operations where synchronization is important.

The frequencies of both the RCLK and WCLK signals may vary from 0 to fMAX

with complete independence. There are no restrictions on the frequency of one

clock input with respect to another.

There are two possible timing modes of operation with these devices: IDT

Standard mode and First Word Fall Through (FWFT) mode.

In IDT Standard mode, the first word written to an empty FIFO will not appear

on the data output lines unless a specific read operation is performed. A read

operation, which consists of activating REN and enabling a rising RCLK edge,

will shift the word from internal memory to the data output lines. Be aware that

in Double Data Rate (DDR) mode only the IDT Standard mode is available.

In FWFT mode, the first word written to an empty FIFO is clocked directly to

the data output lines after three transitions of RCLK. A read operation does not

have to be performed to access the first word written to the FIFO. However,

subsequent words written to the FIFO do require a LOW on REN for access.

The state of the FWFT input during Master Reset determines the timing mode

in use.

For applications requiring more data storage capacity than a single FIFO can

provide, the FWFT timing mode permits depth expansion by chaining FIFOs

in series (i.e. the data outputs of one FIFO are connected to the corresponding

data inputs of the next). No external logic is required.

These FIFOs have four flag pins, EF/OR (Empty Flag or Output Ready), FF/

IR (Full Flag or Input Ready), PAE (Programmable Almost-Empty flag), and

PAF (Programmable Almost-Full flag). The EF and FF functions are selected

in IDT Standard mode. The IR and OR functions are selected in FWFT mode.

PAE and PAF are always available for use, irrespective of timing mode.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

DESCRIPTION (CONTINUED)

PAE and PAF flags can be programmed independently to switch at any point

in memory. Programmable offsets mark the location within the internal memory

that activates the PAE and PAF flags and can only be programmed serially. To

program the offsets, set SEN active and data can be loaded via the Serial Input

(SI) pin at the rising edge of SCLK. To read out the offset registers serially, set

SREN active and data can be read out via the Serial Output (SO) pin at the rising

edge of SCLK. Four default offset settings are also provided, so that PAE can

be marked at a predefined number of locations from the empty boundary and

the PAF threshold can also be marked at similar predefined values from the full

boundary. The default offset values are set during Master Reset by the state

of the FSEL0 and FSEL1 pins.

During Master Reset (MRS), the following events occur: the read and write

pointers are set to the first location of the internal FIFO memory, the FWFT pin

selects IDT Standard mode or FWFT mode, the bus width configuration of the

read and write port is determined by the state of IW and OW, and the default offset

values for the programmable flags are set.

The Partial Reset (PRS) also sets the read and write pointers to the first

location of the memory. However, the timing mode and the values stored in the

programmable offset registers before Partial Reset remain unchanged. The

flags are updated according to the timing mode and offsets in effect. PRS is useful

for resetting a device in mid-operation, when reprogramming programmable

flags would be undesirable.

The timing of the PAE and PAF flags are synchronous to RCLK and WCLK,

respectively. The PAE flag is asserted upon the rising edge of RCLK only and

not WCLK. Similarly the PAF is asserted and updated on the rising edge of

WCLK only and not RCLK.

This device includes a Retransmit from Mark feature that utilizes two control

inputs, MARK and RT (Retransmit). If the MARK input is enabled with respect

to the RCLK, the memory location being read at the point will be marked. Any

subsequent retransmit operation (when RT goes LOW), will reset the read

pointer to this “marked” location.

The device can be configured with different input and output bus widths as

previously stated. These rates are: x40 to x40, x40 to x20,x40 to x10, x20 to

x40, and x10 to x40.

If, at any time, the FIFO is not actively performing an operation, the chip will

automatically power down. Once in the power down state, the standby supply

current consumption is minimized. Initiating any operation (by activating control

inputs) will immediately take the device out of the power down state.

A JTAG test port is provided, here the FIFO has fully functional boundary

Scan feature, compliant with IEEE 1449.1 Standard Test Access Port and

Boundary Scan Architecture.

The Double Data Rate FIFO has the capability of operating in either LVTTL

or HSTL mode. HSTL mode can be selected by enabling the HSTL pin. Both

input and output ports will operate in either HSTL or LVTTL mode, but cannot

be selected independent of one another.

The IDT72T4088/72T4098/72T40108/72T40118 are fabricated using

IDT’s high-speed submicron CMOS technology.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

BM IW OW Write Port Width Read Port Width

L L L x40 x40

H L L x40 x20

H L H x40 x10

H H L x20 x40

H H H x10 x40

TABLE 1 — BUS-MATCHING CONFIGURATION MODES

NOTE:

1. Pin status during Master Reset.

Figure 1. Single Device Configuration Signal Flow Diagram

(x40, x20, x10) DATA OUT (Q

- Q

)(x40, x20, x10) DATA IN (D

- D

)

MASTER RESET (MRS)

READ CLOCK (RCLK)

READ ENABLE (REN)

OUTPUT ENABLE (OE)

EMPTY FLAG/OUTPUT READY (EF/OR)

PROGRAMMABLE ALMOST-EMPTY (PAE)

WRITE CLOCK (WCLK)

WRITE ENABLE (WEN)

WRITE SINGLE DATA RATE (WSDR)

FULL FLAG/INPUT READY (FF/IR)

PROGRAMMABLE ALMOST-FULL (PAF)

IDT

72T4088

72T4098

72T40108

72T40118

PARTIAL RESET (PRS)

FIRST WORD FALL THROUGH (FWFT) RETRANSMIT (RT)

5995 drw03

SERIAL ENABLE(SEN)

INPUT WIDTH (IW) OUTPUT WIDTH (OW)

SERIAL CLOCK (SCLK)

MARK

READ CHIP SELECT (RCS)

RCLK ECHO (ERCLK)

REN ECHO (EREN)

WRITE CHIP SELECT (WCS)

READ SINGLE DATA RATE (RSDR)

SERIAL OUTPUT (SO)

SERIAL INPUT (SI)

SERIAL READ ENABLE(SREN)

WSDR RSDR Write Port Width Read Port Width

H H Double Data Rate Double Data Rate

H L Double Data Rate Single Data Rate

L H Single Data Rate Double Data Rate

L L Single Data Rate Single Data Rate

TABLE 2 — DATA RATE-MATCHING CONFIGURATION MODES

NOTE:

1. Pin status during Master Reset.

2. Data Rate Matching can be used in conjunction with Bus-Matching modes.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

PIN DESCRIPTION

BM(1) Bus-Matching LVTTL During Master Reset, this pin along with IW and OW selects the bus sizes for both write and read

(K2) INPUT ports.

D0-D39 Data Inputs HSTL-LVTTL Data inputs for a 40-, 20-, or 10-bit bus. When in 20- or 10- bit mode, the unused input pins are in a don’t

(See Pin No. INPUT care state. The data bus is sampled on both rising and falling edges of WCLK when WEN is enabled and

table for details) DDR Mode is enabled or on the rising edges of WCLK only in SDR Mode.

EF/OR Empty Flag/ HSTL-LVTTL In the IDT Standard mode, the EF function is selected. EF indicates whether or not the FIFO memory

(M14) Output Ready OUTPUT is empty. In FWFT mode, the OR function is selected. OR indicates whether or not there is valid data

available at the outputs.

ERCLK Echo Read HSTL-LVTTL Read Clock Echo output, must be equal to or faster than the Qn data outputs.

(L16) Clock OUTPUT

EREN Echo Read HSTL-LVTTL Read Enable Echo output, used in conjunction with ERCLK.

(K16) Enable OUTPUT

FF/IR Full Flag/ HSTL-LVTTL In the IDT Standard mode, the FF function is selected. FF indicates whether or not the FIFO memory is

(H3) Input Ready OUTPUT empty. In FWFT mode, the IR function is selected. IR indicates whether or not there is space available

for writing to the FIFO memory.

FSEL0(1) Flag Select Bit 0 LVTTL During Master Reset, this input along with FSEL1 will select the default offset values for the programmable

(J3) INPUT flags PAE and PAF. There are four possible settings available.

FSEL1(1) Flag Select Bit 1 L VTTL During Master Reset, this input along with FSEL0 will select the default offset values for the programmable

(J2) INPUT flags PAE and PAF. There are four possible settings available.

FWFT First Word Fall LVTTL During Master reset, selects First Word Fall Through or IDT Standard mode. FWFT is not available in

(G2) Through INPUT DDR mode. In SDR mode, the first word will always fall through on the rising edge.

HSTL(1) HSTL Select LVTTL This input pin is used to select HSTL or 2.5V LVTTL device operation. If HSTL inputs are required, this

(B7) INPUT input must be tied HIGH, otherwise it must be tied LOW and cannot toggle during operation.

IW(1) Input Width LVTTL During Master Reset, this pin along with OW and BM, selects the bus width of the read and write port.

(K1) INPUT

MARK Mark Read HSTL-LVTTL When this pin is asserted the current location of the read pointer will be marked. Any subsequent Retransmit

(E14) Pointer for INPUT operation will reset the read pointer to this position. There is an unlimited number to times to set the mark

Retransmit location, but only the most recent location marked will be acknowledged.

MRS Master Reset HSTL-LVTTL MRS initializes the read and write pointers to zero and sets the output registers to all zeros. During Master

(J1) INPUT Reset, the FIFO is configured for either FWFT or IDT Standard mode, Bus-Matching configurations, and

programmable flag default settings.

OE Output Enable HSTL-LVTTL When HIGH, data outputs Q0-Q39 are in high impedance. When LOW, the data outputs Q0-Q39 are enabled.

(G15) INPUT No other outputs are affected by OE.

OW(1) Output Width LVTTL During Master Reset, this pin along with IW and BM, selects the bus width of the read and write port.

(L3) INPUT

PAE Programmable HSTL-LVTTL PAE goes HIGH if the number of words in the FIFO memory is greater than or equal to offset n, which is

(L15) Almost-Empty OUTPUT stored in the Empty Offset register. PAE goes LOW if the number of words in the FIFO memory is less than

Flag offset n.

PAF Programmable HSTL-LVTTL PAF goes HIGH if the number of free locations in the FIFO memory is more than offset m, which is stored

(G3) Almost-Full Flag OUTPUT in the Full Offset register. PAF goes LOW if the number of free locations in the FIFO memory is less than

or equal to m.

PRS Partial Reset HSTL-LVTTL PRS initializes the read and write pointers to zero and sets the output registers to all zeros. During Partial

(K3) INPUT Reset, the existing mode (IDT standard or FWFT) and programmable flag settings are not affected.

Q0-Q39 Data Outputs HSTL-LVTTL Data outputs for a 40-, 20-, or 10-bit bus. When in 20- or 10- bit mode, the unused output pins should not

(See Pin No. OUTPUT be connected. The output data is clocked on both rising and falling edges of RCLK when REN is enabled

table for details) and DDR Mode is enabled or on the rising edges of RCLK only in SDR Mode.

RCLK Read Clock HSTL-LVTTL Input clock when used in conjunction with REN for reading data from the FIFO memory and output register.

(G16) INPUT

Symbol & Name I/O TYPE Description

Pin No.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

PIN DESCRIPTION (CONTINUED)

RCS Read Chip Select HSTL-LVTTL RCS provides synchronous enable/disable control of the read port and High-Impedance control of the

(F14) INPUT Qn data outputs, synchronous to RCLK. When using RCS the OE pin must be tied LOW. During Master

or Partial Reset the RCS input is don’t care, if OE is LOW the data outputs will be Low-Impedance

regardless of RCS.

REN Read Enable HSTL-LVTTL When LOW and in DDR mode, REN along with a rising and falling edge of RCLK will send data in FIFO

(F16) INPUT memory to the output register and read the current data in output register. In SDR mode data will only be

read on the rising edge of RCLK only.

RSDR(1) Read Single Data LVTTL When LOW, this input pin sets the read port to Single Data Clock mode. When HIGH, the read port will operate

(L2) Rate INPUT in Double Data Clock mode. This pin must be tied either HIGH or LOW and cannot toggle during operation.

RT Retransmit HSTL-LVTTL RT asserted on the rising edge of RCLK initializes the read pointer to the first location in memory. EF flag

(F15) INPUT is set to LOW (OR to HIGH in FWFT mode). The write pointer, offset registers, and flag settings are not

affected. If a mark has been set via the MARK input pin, then the read pointer will initialize to the mark location

when RT is asserted.

SCLK Serial Clock LVTTL A rising edge of SCLK will clock the serial data present on the SI input into the offset registers provided

(H15) INPUT that SEN is enabled. A rising edge of SCLK will also read data out of the offset registers provided that SREN

is enabled.

SEN Serial Input HSTL-LVTTL SEN used in conjunction with SI and SCLK enables serial loading of the programmable flag offsets.

(J15) Enable INPUT

SREN Serial Read HSTL-LVTTL SREN used in conjunction with SO and SCLK enables serial reading of the programmable flag offsets.

(J16) Enable INPUT

SI Serial Input HSTL-LVTTL This input pin is used to load serial data into the programmable flag offsets. Used in conjunction with SEN

(H16) INPUT and SCLK.

SO Serial Output HSTL-LVTTL This output pin is used to read data from the programmable flag offsets. Used in conjunction with SREN

(K15) OUTPUT and SCLK.

TCK(2) JTAG Clock HSTL-LVTTL Clock input for JTAG function. One of four terminals required by IEEE Standard 1149.1-1990. Test

(F1) INPUT operations of the device are synchronous to TCK. Data from TMS and TDI are sampled on the rising edge

of TCK and outputs change on the falling edge of TCK. If the JTAG function is not used this signal needs

to be tied to GND.

TDI(2) JTAG Test Data HSTL-LVTTL One of four terminals required by IEEE Standard 1149.1-1990. During the JTAG boundary scan operation,

(E2) Input INPUT test data serially loaded via the TDI on the rising edge of TCK to either the Instruction Register, ID Register

and Bypass Register. An internal pull-up resistor forces TDI HIGH if left unconnected.

TDO(2) JTAG Test Data HSTL-LVTTL One of four terminals required by IEEE Standard 1149.1-1990. During the JTAG boundary scan operation,

(F3) Output OUTPUT test data serially loaded output via the TDO on the falling edge of TCK from either the Instruction Register,

ID Register and Bypass Register. This output is high impedance except when shifting, while in SHIFT-

DR and SHIFT-IR controller states.

TMS(2) JTAG Mode HSTL-LVTTL TMS is a serial input pin. One of four terminals required by IEEE Standard 1149.1-1990. TMS directs the

(F2) Select INPUT the device through its TAP controller states. An internal pull-up resistor forces TMS HIGH if left unconnected.

TRST(2) JTAG Reset HSTL-LVTTL TRST is an asynchronous reset pin for the JTAG controller. The JTAG TAP controller does not

(E3) INPUT automatically reset upon power-up, thus it must be reset by either this signal or by setting TMS= HIGH for

five TCK cycles. If the TAP controller is not properly reset then the FIFO outputs will always be in high-

impedance. If the JTAG function is used but the user does not want to use TRST, then TRST can be tied

with MRS to ensure proper FIFO operation. If the JTAG function is not used then this signal needs to be

tied to GND. An internal pull-up resistor forces TRST HIGH if left unconnected.

WCLK Write Clock HSTL-LVTTL Input clock when used in conjunction with WEN for writing data into the FIFO memory.

(G1) INPUT

WCS Write Chip Select HSTL-LVTTL The WCS pin can be regarded as a second WEN input, enabling/disabling write operations.

(H2) INPUT

WEN Write Enable HSTL-LVTTL When LOW and in DDR mode, WEN along with a rising and falling edge of WCLK will write data into the

(H1) INPUT FIFO memory. In SDR mode data will only be read on the rising edge of RCLK only.

Symbol & Name I/O TYPE Description

Pin No.

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CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

PIN DESCRIPTION (CONTINUED)

Symbol & Name I/O TYPE Description

Pin No.

WSDR(1) Write Single Data LVTTL When LOW, this input pin sets the write port to Single Data Clock mode. When HIGH, the write port will

(L1) Rate INPUT operate in Double Data Clock mode. This pin must be tied either HIGH or LOW and cannot toggle

during operation.

VCC +2.5V Supply INPUT There are Vcc supply inputs and must be connected to the 2.5V supply rail.

(See below)

VDDQ O/P Rail Voltage INPUT This pin should be tied to the desired voltage rail for providing power to the output drivers. Nominally 1.5V

(See below) or 1.8V for HSTL, 2.5V for LVTTL.

GND Core Ground Pin INPUT These are Ground pins are for the core device and must be connected to the GND rail.

(See below)

Vref Reference INPUT This is a Voltage Reference input and must be connected to a voltage level determined in the

(T3) Voltage Recommended DC Operating Conditions section. This provides the reference voltage when using HSTL

class inputs. If HSTL class inputs are not being used, this pin must be connected to GND.

PIN NUMBER TABLE

Symbol Name I/O TYPE Pin Number

D0-39 Data Inputs HSTL-LVTTL D0-C3, D1-A4, D2-B4, D3-C4, D4-A5, D5-B5, D6-C5, D7-A6, D8-B6, D9-A7, D10-R7, D11-T7,

INPUT D12-R6, D13-T6, D14-R5, D15-T5, D16-R4, D17-T4, D18-P3, D19-R3, D20-N2, D21-P2, D22-R2,

D23-N1, D24-P1, D25-R1, D26-N3, D(27-29)-M(1-3), D30-E1, D(31-33)-D(3-1), D34-C1,

D(35,36)-B(1,2), D37-C2, D38-A3, D39-B3

Q0-39 Data Outputs HSTL-LVTTL Q0-B10, Q1-A10, Q2-B11, Q3-A11, Q4-B12, Q5-A12, Q6-B13, Q7-A13, Q8-B14, Q9-A14, Q10-T14

OUTPUT Q11-R14, Q12-T13, Q13-R13, Q14-T12, Q15-R12, Q16-T11, Q17-R11, Q18-T10, Q19-R10,

Q(20,21)-C(14,15), Q(22,23)-B(15,16), Q24-C16, Q(25-27)-D(16-14), Q(28,29)-E(16,15),

Q(30,31)-M(15,16), Q(32-34)- N(14-16), Q(35-37)-P(14-16), Q(38,39)-R(15,16)

VCC +2.5V Supply INPUT A(1,2), C(6,7), D(4-7), K4, L4, M4, N(4-7), P(5-7), T(1,2)

VDDQ O/P Rail Voltage INPUT A(15,16), C(10-13), D(10-13), E13, F(4,13), G(4,14), H(4,14), J14, K14, L14, M13, N(10-13),

P(10-13), T(15,16)

GND Ground Pin INPUT A(8,9), B(8,9), C(8,9), D(8,9), E4, G(7-10,13), H(7-10,13), J(4,7-10,13), K(7-10,13), L13, N(8,9),

P(4,8,9), R(8,9), T(8,9)

NOTES:

1. Inputs should not change state after Master Reset.

2. These pins are for the JTAG port. Please refer to pages 25-28 and Figures 5-7.

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IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Symbol Rating Commercial Unit

VTERM Terminal Voltage –0.5 to +3.6(2) V

with respect to GND

TSTG Storage Temperature –55 to +125 °C

IOUT DC Output Current –50 to +50 mA

DC ELECTRICAL CHARACTERISTICS

(Commercial: VCC = 2.5V ± 0.125V, T A = 0°C to +70°C;Industrial: VCC = 2.5V ± 0.125V, TA = -40°C to +85°C)

Symbol Parameter Min. Typ. Max. Unit

VCC Supply Voltage 2.375 2.5 2.625 V

GND Supply Voltage 0 0 0 V

VIH Input High Voltage  LVTTL 1.7 — 3.45 V

 eHSTL VREF+0.2 — — V

 HSTL VREF+0.2 — — V

VIL Input Low Voltage  LVTTL -0.3 — 0.7 V

 eHSTL — — VREF-0.2 V

 HSTL — — VREF-0.2 V

VREF Voltage Reference Input  eHSTL 0.8 0.9 1.0 V

(HSTL only)  HSTL 0.68 0.75 0.9 V

TAOperating Temperature Commercial 0 — 70 °C

TAOperating Temperature Industrial -40 — 85 °C

Symbol Parameter Min. Max. Unit

ILI Input Leakage Current –10 10 µA

ILO Output Leakage Current –10 10 µA

VOH(5) Output Logic “1” Voltage, IOH = –8 mA @VDDQ = 2.5V ± 0.125V (LVTTL) V DDQ -0.4 — V

IOH = –8 mA @VDDQ = 1.8V ± 0.1V (eHSTL) VDDQ -0.4 — V

IOH = –8 mA @VDDQ = 1.5V ± 0.1V (HSTL) VDDQ -0.4 — V

VOL Output Logic “0” Voltage, IOL = 8 mA @VDDQ = 2.5V ± 0.125V (LVTTL) — 0.4V V

IOL = 8 mA @VDDQ = 1.8V ± 0.1V (eHSTL) — 0.4V V

IOL = 8 mA @VDDQ = 1.5V ± 0.1V (HSTL) — 0.4V V

ICC1(1,2) Active VCC Current (VCC = 2.5V) I/O = LVTTL — 2 0 mA

I/O = HSTL — 60 m A

I/O = eHSTL — 60 m A

ICC2(1) Standby VCC Current (VCC = 2.5V) I/O = LVTTL — 1 0 mA

I/O = HSTL — 50 m A

I/O = eHSTL — 50 m A

ABSOLUTE MAXIMUM RATINGS

RECOMMENDED DC OPERATING CONDITIONS

NOTES:

1 . Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may cause

permanent damage to the device. This is a stress rating only and functional operation

of the device at these or any other conditions above those indicated in the operational

sections of this specification is not implied. Exposure to absolute maximum rating

conditions for extended periods may affect reliability.

2. Compliant with JEDEC JESD8-5. VCC terminal only.

Symbol Parameter(1) Conditions Max. Unit

CIN(2,3) Input VIN = 0V 10(3) pF

Capacitance

COUT(1,2) Output VOUT = 0V 10 pF

Capacitance

CAPACITANCE (TA = +25°C, f = 1.0MHz)

NOTES:

1. With output deselected, (OE ≥ VIH).

2. Characterized values, not currently tested.

3. CIN for Vref is 20pF.

NOTES:

1 . Both WCLK and RCLK toggling at 20MHz. Data inputs toggling at 10MHz. WCS = HIGH, REN or RCS = HIGH.

2. Typical ICC1 calculation:for LVTTL I/O ICC1 (mA) = 0.6mA x fs, fs = WCLK frequency = RCLK frequency (in MHz)

for HSTL or eHSTL I/O ICC1 (mA) = 38mA + (0.7mA x fs), fs = WCLK frequency = RCLK frequency (in MHz)

3. Typical IDDQ calculation: With Data Outputs in High-Impedance: IDDQ (mA) = 0.15mA x fs

With Data Outputs in Low-Impedance: IDDQ (mA) = (CL x VDDQ x fs x 2N)/2000

fs = WCLK frequency = RCLK frequency (in MHz), VDDQ = 2.5V for LVTTL; 1.5V for HSTL; 1.8V for eHSTL, N = Number of outputs switching.

tA = 25°C, CL = capacitive load (pf)

4. Total Power consumed: PT = [(VCC x ICC) + (VDDQ x IDDQ)].

5. Outputs are not 3.3V tolerant.

NOTE:

1. VREF is only required for HSTL or eHSTL inputs. VREF should be tied LOW for LVTTL operation.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

AC ELECTRICAL CHARACTERISTICS(1)

(Commercial: VCC = 2.5V ± 5%, TA = 0°C to +70°C;Industrial: VCC = 2.5V ± 5%, TA = -40 °C to +85°C)

Commercial Commercial Com’l & Ind’l(2) Commercial

IDT72T4088L4 IDT72T4088L5 IDT72T4088L6-7 IDT72T4088L10

IDT72T4098L4 IDT72T4098L5 IDT72T4098L6-7 IDT72T4098L10

IDT72T40108L4 IDT72T40108L5 IDT72T40108L6-7 IDT72T40108L10

IDT72T40118L4 IDT72T40118L5 IDT72T40118L6-7 IDT72T40118L10

Symbol Parameter Min. Max. Min. Max. Min. Max. Min. Max. Unit

fS1 Clock Cycle Frequency SDR — 250 — 200 — 150 — 100 MHz

fS2 Clock Cycle Frequency DDR — 150 — 150 — 150 — 100 MHz

tAData Access Time 0.6 3.2 0.6 3.6 0.6 3.8 0.6 4.5 ns

tASO Data Access Serial Output Time 0.6 3.2 0.6 3.6 0.6 3.8 0.6 4.5 ns

tCLK1 Clock Cycle Time SDR 4 — 5 — 6.7 — 10 — ns

tCLK2 Clock Cycle Time DDR 6.7 — 6.7 — 6.7 — 10 — ns

tCLKH1 Clock High Time SDR 1.8 — 2. 3 — 2. 8 — 4.5 — ns

tCLKH2 Clock High Time DDR 2. 8 — 2.8 — 2. 8 — 4 .5 — ns

tCLKL1 Clock Low Time SDR 1.8 — 2.3 — 2. 8 — 4. 5 — ns

tCLKL2 Clock Low Time DDR 2. 8 — 2. 8 — 2 . 8 — 4 .5 — n s

tDS Data Setup Time 1.2 — 1.5 — 2.0 — 3.0 — ns

tDH Data Hold Time 0.5 — 0.5 — 0.5 — 0.5 — ns

tENS Enable Setup Time 1.2 — 1.5 — 2.0 — 3.0 — ns

tENH Enable Hold Time 0.5 — 0.5 — 0.5 — 0.5 — ns

tWCSS WCS setup time 1.2 — 1.5 — 2.0 — 3.0 — ns

tWCSH WCS hold time 0.5 — 0.5 — 0.5 — 0.5 — ns

fCClock Cycle Frequency (SCLK) — 10 — 10 — 10 — 10 MHz

tSCLK Serial Clock Cycle 100 — 100 — 100 — 100 — ns

tSCKH Serial Clock High 45 — 45 — 45 — 45 — n s

tSCKL Serial Clock Low 45 — 45 — 45 — 45 — n s

tSDS Serial Data In Setup 15 — 15 — 15 — 15 — ns

tSDH Serial Data In Hold 5 — 5 — 5 — 5 — ns

tSENS Serial Enable Setup 5 — 5 — 5 — 5 — ns

tSENH Serial Enable Hold 5 — 5 — 5 — 5 — ns

tRS Reset Pulse Width(3) 30 — 30 — 30 — 30 — ns

tRSS Reset Setup Time 15 — 15 — 15 — 15 — ns

tHRSS HSTL Reset Setup Time 4 — 4 — 4 — 4 — µs

tRSR Reset Recovery Time 10 — 10 — 10 — 10 — ns

tRSF Reset to Flag and Output Time — 10 — 1 2 — 15 — 15 ns

tOLZ Output Enable to Output in Low Z(4) 0—0—0—0—ns

tOE Output Enable to Output Valid — 3.2 — 3.6 — 3.8 — 4.5 ns

tOHZ Output Enable to Output in High Z(4) — 3.2 — 3.6 — 3.8 — 4.5 ns

tWFF Write Clock to FF or IR — 3.2 — 3.6 — 3.8 — 4.5 ns

tREF Read Clock to EF or OR — 3.2 — 3.6 — 3.8 — 4.5 ns

tPAFS Write Clock to Programmable Almost-Full Flag — 3.2 — 3.6 — 3.8 — 4.5 ns

tPAES Read Clock to Programmable Almost-Empty Flag — 3.2 — 3.6 — 3.8 — 4.5 ns

tERCLK RCLK to Echo RCLK output — 3. 6 — 4 — 4. 3 — 5 n s

tCLKEN RCLK to Echo REN output — 3 .2 — 3 .6 — 3 .8 — 4. 5 ns

tRCSLZ RCLK to Active from High-Z — 3 .2 — 3.6 — 3. 8 — 4 .5 ns

tRCSHZ RCLK to High-Z(4) — 3.2 — 3.6 — 3.8 — 4.5 ns

tSKEW1 Skew time between RCLK and WCLK for EF/OR and FF/IR 3.5—4—5—7—ns

tSKEW2 Skew time between RCLK & WCLK for EF/OR & FF/IR in DDR mode 3.5—4—5—7—ns

tSKEW3 Skew time between RCLK and WCLK for PAE and PAF 4—5—6—8—ns

NOTES:

1. All AC timings apply to both IDT Standard mode and First Word Fall Through mode.

2. Industrial temperature range product for the 6-7ns speed grade is available as a standard device. All other speed grades are available by special order.

3. Pulse widths less than minimum values are not allowed.

4. Values guaranteed by design, not currently tested.

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TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Input Pulse Levels 0.25 to 1.25V

Input Rise/Fall Times 0.4ns

Input Timing Reference Levels 0.75

Output Reference Levels VDDQ/2

HSTL

1.5V AC TEST CONDITIONS

Figure 2b. Lumped Capacitive Load, Typical Derating

AC TEST LOADS

Figure 2a. AC Test Load

Input Pulse Levels 0.4 to 1.4V

Input Rise/Fall Times 0.4ns

Input Timing Reference Levels 0.9

Output Reference Levels VDDQ/2

EXTENDED HSTL

1.8V AC TEST CONDITIONS

Input Pulse Levels GND to 2.5V

Input Rise/Fall Times 1ns

Input Timing Reference Levels VCC/2

Output Reference Levels VDDQ/2

2.5V LVTTL

2.5V AC TEST CONDITIONS

NOTE:

1. VDDQ = 1.5V±.

NOTE:

1. VDDQ = 1.8V±.

NOTE:

1. For LVTTL VCC = VDDQ.

5995 drw04

Ω

VDDQ/2

I/O Z

= 50

Ω

5995 drw04a

20 30 50 80 100 200

Capacitance (pF)

tCD

(Typical, ns)

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

OUTPUT ENABLE & DISABLE TIMING

OE &

OLZ

100mV

OHZ

100mV

Output

Normally

LOW

Output

Normally

HIGH

5995 drw04b

Output

Enable

Output

Disable

READ CHIP SELECT ENABLE & DISABLE TIMING

VIH

RCS

VIL

ENS

ENH

RCSLZ

RCLK

100mV

RCSHZ

100mV

Output

Normally

LOW

Output

Normally

HIGH

VOL

VOH

5995 drw04c

NOTES:

1. REN is HIGH.

2. RCS is LOW.

NOTES:

1. REN is HIGH.

2. OE is LOW.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

FUNCTIONAL DESCRIPTION

TIMING MODES: IDT STANDARD vs FIRST WORD FALL THROUGH

(FWFT) MODE

The IDT72T4088/72T4098/72T40108/72T40118 support two different

timing modes of operation: IDT Standard mode or First Word Fall Through

(FWFT) mode. The selection of which mode will operate is determined during

Master Reset, by the state of the FWFT input.

During Master Reset, if the FWFT pin is LOW, then IDT Standard mode will

be selected. This mode uses the Empty Flag (EF) to indicate whether or not there

are any words present in the FIFO. It also uses the Full Flag function (FF) to

indicate whether or not the FIFO has any free space for writing. In IDT Standard

mode, every word read from the FIFO, including the first, must be requested

using the Read Enable (REN) and RCLK.

If the FWFT pin is HIGH during Master Reset, then FWFT mode will be

selected. This mode uses Output Ready (OR) to indicate whether or not there

is valid data at the data outputs (Qn). It also uses Input Ready (IR) to indicate

whether or not the FIFO has any free space for writing. In the FWFT mode, the

first word written to an empty FIFO goes directly to Qn after three RCLK rising

edges, applying REN = LOW is not necessary. However, subsequent words

must be accessed using the Read Enable (REN) and RCLK.

Various signals, in both inputs and outputs operate differently depending on

which timing mode is in effect.

IDT ST ANDARD MODE

In this mode, the status flags FF, PAF, PAE, and EF operate in the manner

outlined in Table 4. To write data into the FIFO, Write Enable (WEN) must be

LOW. Data presented to the DATA IN lines will be clocked into the FIFO on

subsequent transitions of the Write Clock (WCLK). After the first write is

performed, the Empty Flag (EF) will go HIGH. Subsequent writes will continue

to fill up the FIFO. The Programmable Almost-Empty flag (PAE) will go HIGH

after n + 1 words have been loaded into the FIFO, where n is the empty offset

value. The default setting for these values are listed in Table 3. This parameter

is also user programmable. See section on Programmable Flag Offset Loading.

Continuing to write data into the FIFO without performing read operations will

cause the Programmable Almost-Full flag (PAF) to go LOW. Again, if no reads

are performed, the PAF will go LOW after (16,384-m) writes for the IDT72T4088,

(32,768-m) writes for the IDT72T4098, (65,536-m) writes for the IDT72T40108

and (131,072-m) writes for the IDT72T40118. The offset “m” is the full offset

value. The default setting for these values are listed in Table 3. This parameter

is also user programmable. See the section on Programmable Flag Offset

When the FIFO is full, the Full Flag (FF) will go LOW, inhibiting further write

operations. If no reads are performed after a reset, FF will go LOW after D writes

to the FIFO. D = 16,384 writes for the IDT72T4088, 32,768 writes for the

IDT72T4098, 65,536 writes for the IDT72T40108 and 131,072 writes for the

IDT72T40118, respectively.

If the FIFO is full, the first read operation will cause FF to go HIGH. Subsequent

read operations will cause PAF to go HIGH at the conditions described in Table

4 If further read operations occur, without write operations, PAE will go LOW

when there are n words in the FIFO, where n is the empty offset value.

Continuing read operations will cause the FIFO to become empty. Then the last

word has been read from the FIFO, the EF will go LOW inhibiting further read

operations. REN is ignored when the FIFO is empty.

When configured in IDT Standard mode, the EF and FF outputs are double

configured in both Single Data Rate and Double Data Rate mode.

Relevant timing diagrams for IDT Standard mode can be found in Figure 10,

11, 12, 13, 14, 15, 16, 17, 18 and 23.

FIRST WORD FALL THROUGH MODE (FWFT)

In this mode, the status flags OR, IR, PAE, and PAF operate in the manner

outlined in Table 5. To write data into to the FIFO, WEN must be LOW. Data

presented to the DATA IN lines will be clocked into the FIFO on subsequent

transitions of WCLK. After the first write is performed, the Output Ready (OR)

flag will go LOW. Subsequent writes will continue to fill up the FIFO. PAE will go

HIGH after n + 2 words have been loaded into the FIFO, where n is the empty

offset value. The default setting for these values are listed in Table 3. This

parameter is also user programmable. See section on Programmable Flag

Offset Loading.

Continuing to write data into the FIFO without performing read operations will

cause the Programmable Almost-Full flag (PAF) to go LOW. Again, if no reads

are performed, the PAF will go LOW after (16,385-m) writes for the IDT72T4088,

(32,769-m) writes for the IDT72T4098, (65,537-m) writes for the IDT72T40108

and (131,073-m) writes for the IDT72T40118. The offset “m” is the full offset

value. The default setting for these values are listed in Table 3. This parameter is

also user programmable. See the section on Programmable Flag Offset Loading.

When the FIFO is full, the Input Ready (IR) will go LOW, inhibiting further write

operations. If no reads are performed after a reset, IR will go LOW after D writes

to the FIFO. D = 16,385 writes for the IDT72T4088, 32,769 writes for the

IDT72T4098, 65,537 writes for the IDT72T40108 and 131,073 writes for the

IDT72T40118, respectively. Note that the additional word in FWFT mode is due

to the capacity of the memory plus output register.

If the FIFO is full, the first read operation will cause IR to go HIGH. Subsequent

read operations will cause PAF to go HIGH at the conditions described in Table

5. If further read operations occur, without write operations, PAE will go LOW

when there are n words in the FIFO, where n is the empty offset value.

Continuing read operations will cause the FIFO to become empty. Then the last

word has been read from the FIFO, the OR will go HIGH inhibiting further read

operations. REN is ignored when the FIFO is empty.

When configured in FWFT mode, the OR flag output is triple register-buffered

and the IR flag output is double register-buffered. FWFT mode is only available

when the device is configured in Single Data Rate mode.

Relevant timing diagrams for IDT Standard mode can be found in Figure 19,

20, 21, 22 and 24.

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TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

IDT72T4088, 72T4098, 72T40108, 72T401 18

FSEL1 FSEL0 Offsets n,m

H H 255

L H 127

HL63

LL7

TABLE 3 — DEFAULT PROGRAMMABLE

FLAG OFFSETS

NOTES:

1. n = empty offset for PAE.

2 . m = full offset for PAF.

PROGRAMMING FLAG OFFSETS

Full and Empty Flag offset values are user programmable. The IDT72T4088/

72T4098/72T40108/72T40118 have internal registers for these offsets. There

are four selectable default offset values during Master Reset. These offset values

are shown in Table 3. The offset values can also be programmed serially into

the FIFO. To load offset values, set SEN LOW and the rising edge of SCLK will

IDT72T4088 IDT72T4098

1 to n

(1)

(16,384-m) to 16,383

16,384

IDT72T40118

TABLE 4  STATUS FLAGS FOR IDT STANDARD MODE

TABLE 5  STATUS FLAGS FOR FWFT MODE

FF PAF PAE EF

HHLL

HHLH

HHHH

HL HH

LLHH

Number of

Words in

FIFO

5995 drw05

IDT72T40108

(8,193) to (16,384-(m+1))

(32,768-m) to 32,767

32,768

(16,385) to (32,768-(m+1))

(65,536-m) to 65,535

65,536

(32,769) to (65,536-(m+1))

(131,072-m) to 131,071

131,072

(65,537) to (131,072-(m+1))

IDT72T4088 IDT72T4098

1 to n+1

(1)

(16,385-m) to 16,384

16,385

IDT72T40118

IR PAF PAE OR

LHLH

LHLL

L HHL

LLHL

HLHL

Number of

Words in

FIFO

IDT72T40108

(8,194) to (16,385-(m+1))

(32,769-m) to 32,768

32,769

(16,386) to (32,769-(m+1))

(65,537-m) to 65,536

65,537

(32,770) to (65,537-(m+1))

(131,073-m) to 131,072

131,073

(65,538) to (131,073-(m+1))

1 to n

(1)

1 to n

(1)

1 to n

(1)

1 to n+1

(1)

1 to n+1

(1)

1 to n+1

(1)

NOTE:

1. See table 3 for values for n, m.

NOTE:

1. See table 3 for values for n, m.

2. FWFT mode available only in Single Data Rate mode.

load data from the SI input into the offset registers. SCLK runs at a nominal speed

of 10MHz at the maximum. The programming sequence starts with one bit for

each SCLK rising edge, starting with the Empty Offset LSB and ending with the

Full Offset MSB. The total number of bits per device is listed in Figure 3,

Programmable Flag Offset Programming Sequence. See Figure 25, Loading

of Programmable Flag Registers, for the timing diagram for this mode. The PAE

and PAF can show a valid status only after the complete set of bits (for all offset

registers) has been entered. The registers can be reprogrammed as long as

the complete set of new offset bits is entered.

In addition to loading offset values into the FIFO, it is also possible to read

the current offset values. Similar to loading offset values, set SREN LOW and

the rising edge of SCLK will send data from the offset registers out to the SO output

port. When initializing a read to the offset registers, data will be read starting from

the first location in the register, regardless of where it was last read.

Figure 3, Programmable Flag Offset Programming Sequence, summarizes

the control pins and sequence for programming offset registers and reading and

writing into the FIFO.

The offset registers may be programmed (and reprogrammed) any time

after Master Reset. V alid programming ranges are from 0 to D-1.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 3. Programmable Flag Offset Programming Sequence

NOTES:

1. The programming sequence applies to both IDT Standard and FWFT modes.

2. When the input or output ports are in DDR mode, the depth is reduced by half but the overall density remains the same. For example, the IDT72T4088 in SDR mode is

16,384 x 40 = 655,360, in DDR mode the configuration becomes 8,192 x 80 = 655,360. In both cases, the total density are the same.

WCLK RCLK

WSDR

RSDR

SEN

SREN

IDT72T4088

IDT72T4098

IDT72T40108

IDT72T40118

SCLK

5995 drw06

WEN

REN

In SDR Mode

X11 XX Write Memory (DDR)

X01

X01 XX Write Memory (SDR)

X01

X11 XX Read Memory (DDR)

X10

X10 XX Read Memory (SDR)

X10

XXX No Operation

X11 XXX

1 bit for each rising SCLK edge

Starting with Empty Offset

(LSB) Ending with Full Offset

(MSB)

Serial write to registers:

28 bits for the IDT72T4088

30 bits for the IDT72T4098

32 bits for the IDT72T40108

34 bits for the IDT72T40118

Serial write to registers:

In DDR Mode

26 bits for the IDT72T4088

28 bits for the IDT72T4098

30 bits for the IDT72T40108

32 bits for the IDT 72T40118

1 bit for each rising SCLK edge

Starting with Empty Offset

(LSB) Ending with Full Offset

(MSB)

In SDR Mode

1 bit for each rising SCLK edge

Starting with Empty Offset

(LSB) Ending with Full Offset

(MSB)

Serial read from registers:

28 bits for the IDT72T4088

30 bits for the IDT72T4098

32 bits for the IDT72T40108

34 bits for the IDT72T40118

In DDR Mode

1 bit for each rising SCLK edge

Starting with Empty Offset

(LSB) Ending with Full Offset

(MSB)

Serial read from registers:

26 bits for the IDT72T4088

28 bits for the IDT72T4098

30 bits for the IDT72T40108

32 bits for the IDT72T40118

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

RETRANSMIT FROM MARK OPERA TION

The Retransmit from Mark feature allows FIFO data to be read repeatedly

starting at a user-selected position. The FIFO is first put into retransmit mode

that will “mark” a beginning word and also set a pointer that will prevent

ongoing FIFO write operations from over-writing retransmit data. The retrans-

mit data can be read repeatedly any number of times from the “marked”

position. The FIFO can be taken out of retransmit mode at any time to allow

normal device operation. The “mark” position can be selected any number of

times, each selection over-writing the previous mark location.

In Double Data Rate, data is always marked in pairs. That is, the unit of data

read on the rising and falling edge of WCLK. If the data marked was read on

the falling edge of RCLK, then the marked data will be the unit of data read from

the rising and falling edge of that particular RCLK edge. Refer to Figure 23,

Retransmit from Mark in Double Data Rate Mode, for the timing diagram in

this mode. Retransmit operation is available in both IDT standard and FWFT

modes.

During IDT standard mode the FIFO is put into retransmit mode by a Low-

to-High transition on RCLK when the MARK input is HIGH and EF is HIGH.

The rising RCLK edge marks the data present in the FIFO output register as

the first retransmit data. Again, the data is marked in pairs. Thus if the data

marked was read on the falling edge of RCLK, the first part of retransmit will

read out the data read on the rising edge of RCLK, followed by the data on the

falling edge (the marked data). The FIFO remains in retransmit mode until a

rising edge on RCLK occurs while MARK is LOW .

Once a marked location has been set, a retransmit can be initiated by a

rising edge on RCLK while the Retransmit input (RT) is LOW . REN must be

HIGH (reads disabled) before bringing RT LOW. The device indicates the start

of retransmit setup by setting EF LOW, also preventing reads. When EF goes

HIGH, retransmit setup is complete and read operations may begin starting

with the first unit of data at the MARK location. Since IDT standard mode is

selected, every word read including the first “marked” word following a re-

transmit setup requires a LOW on REN.

Note, write operations may continue as normal during all retransmit functions,

however write operations to the “marked” location will be prevented. See Figure

23, Retransmit from Mark in Double Data Rate Mode, for the relevant timing

diagram.

During FWFT mode the FIFO is put into retransmit mode by a rising RCLK

edge when the MARK input is HIGH and OR is LOW . The rising RCLK edge

marks the data present in the FIFO output register as the first retransmit data.

The data is marked in pairs. The FIFO remains in retransmit mode until a

rising RCLK edge occurs while MARK is LOW.

Once a marked location has been set, a retransmit can be initiated by a

rising RCLK edge while the Retransmit input (RT) is LOW. REN must be

HIGH (reads disabled) before bringing RT LOW. The device indicates the

start of retransmit setup by setting OR HIGH, preventing read operations.

When OR goes LOW , retransmit setup is complete and on the next rising

RCLK edge (RT goes HIGH), the contents of the first retransmit location are

loaded onto the output register . Since FWFT mode is selected, the first word

appears on the outputs regardless of REN, a LOW on REN is not required for

the first word. Reading all subsequent words requires a LOW on REN to

enable the rising RCLK edge. See Figure 24, Retransmit from Mark (FWFT

mode) for the relevant timing diagram.

Before a retransmit can be performed, there must be at least 1280 bits

(or 160 bytes) of data between the write pointer and mark location.

That is, 40 bits x32 for the x40 mode, 20 bits x64 for the x20 mode, and 10 bits

x128 for the x10 mode. Also, once the Mark is set, the write pointer will not

increment past the marked location, preventing overwrites of retransmit data.

HSTL/LVTTL I/O

This device supports both LVTTL and HSTL logic levels on the input and

output signals. If LVTTL is desired, a LOW on the HSTL pin will set the inputs

and outputs to LVTTL mode. If HSTL is desired, a HIGH on the HSTL pin will

set the inputs and outputs to HSTL mode. VREF is the input voltage reference

used in HSTL mode. Typically a logic HIGH in HSTL would be Vref + 0.2V and

a logic LOW would be VREF – 0.2V. Table 6 illustrates which pins are and are

not associated with this feature. Note that all “Static Pins” must be tied to Vcc or

GND. These pins are LVTTL only and are purely device configuration pins.

HSTL SELECT STATIC PINS

HIGH = HSTL L VTTL ONL Y

LOW = L VTTL

Write Port Read Port Signal Pins Static Pins

Dn (I/P) Qn (O/P) EF/OR (O/P) SCLK (I/P) TRST (I/P) IW (I/P)

WCLK (I/P) RCLK (I/P) PAF (O/P) SI (I/P) TDI (I/P) OW (I/P)

WEN (I/P) REN (I/P) PAE (O/P) SO (O/P) TDO (O/P) BM ((I/P)

WCS (I/P) RCS (I/P) FF/IR (O/P) MRS (I/P) SEN (I/P) HSTL (I/P)

MARK (I/P) ERCLK (O/P) PRS (I/P) SREN (I/P) FSEL1 (I/P)

OE (I/P) EREN (O/P) TCK (I/P) FSEL0 (I/P)

RT (I/P) TMS (I/P) FWFT (I/P)

WSDR (I/P)

RSDR (I/P)

TABLE 6 — I/O CONFIGURATION

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

SIGNAL DESCRIPTION

INPUTS:

DATA IN (D0 – D n)

(D0 – D39) are data inputs for the 40-bit wide data, (D0 – D19) are data

inputs for the 20-bit wide data, or (D0 – D9) are data inputs for 10-bit wide data.

CONTROLS:

MASTER RESET (MRS)

A Master Reset is accomplished whenever the MRS input is taken to a LOW

state. This operation sets the internal read and write pointers to the first location

of the RAM array . PAE will go LOW and PAF will go HIGH.

If FWFT is LOW during Master Reset then IDT Standard mode along with

EF and FF are selected. EF will go LOW and FF will go HIGH, If FWFT is

HIGH, then the First Word Fall Through (FWFT) mode, along with IR and OR

are selected. OR will go HIGH and IR will go LOW .

All control settings such as OW, IW, BM, WSDR, RSDR, FSEL0 and FSEL1

are defined during the Master Reset cycle.

During a Master Reset the output register is initialized to all zeros. A Master

Reset is required after power up before a write operation can take place. MRS

is asynchronous.

See Figure 8, Master Reset Timing, for the relevant timing diagram.

P ARTIAL RESET (PRS)

A Partial Reset is accomplished whenever the PRS input is taken to a LOW

state. As in the case of the Master Reset, the internal read and write pointers

are set to the first location of the RAM array . PAE goes LOW and PAF goes

HIGH.

Whichever mode was active at the time of Partial Reset will remain active

after Partial Reset. If IDT Standard Mode is active, then FF will go HIGH and

EF will go LOW. If the First Word Fall Through mode is active, then OR will go

HIGH and IR will go LOW .

Following Partial Reset, all values held in the offset registers remain un-

changed. The output register is initialized to all zeroes. PRS is asynchronous.

Partial Reset is useful for resetting the read and write pointers to zero without

affecting the values of the programmable flag offsets and the timing mode of the

FIFO.

See Figure 9, Partial Reset Timing, for the relevant timing diagram.

RETRANSMIT (RT)

The Retransmit (RT) input is used in conjunction with the MARK input.

T ogether they provide a means by which data previously read out of the FIFO

can be reread any number of times. When the retransmit operation is selected

(i.e. after data has been marked), a rising edge on RCLK while RT is LOW will

reset the read pointer back to the memory location set by the user via the

MARK input.

If IDT Standard mode has been selected, the EF flag will go LOW on the

rising edge of RCLK that retransmit was initiated (i.e. rising edge of RCLK

while RT is LOW). EF will go back to HIGH on the next rising edge of RCLK,

which signifies that retransmit setup is complete. The next read operation will

access data from the “marked” memory location.

Subsequent retransmit operations may be performed, each time the read

pointer returning to the “marked” location. See Figure 23, Retransmit from

Mark in Double Data Rate Mode (IDT Standard Mode) for the relevant timing

diagram.

If FWFT mode has been selected, the OR flag will go HIGH on the rising

edge of RCLK that retransmit was initiated. OR will return LOW on the next

rising edge of RCLK, which signifies that retransmit setup is complete. Under

FWFT mode, the contents in the marked memory location will be loaded onto

the output register on the next rising edge of RCLK. To access all subsequent

data, a read operation will be required.

Subsequent retransmit operations may be performed, each time the read

pointer returning to the “marked” location. See Figure 24, Retransmit from

Mark (FWFT Mode) for the relevant timing diagram.

MARK

The MARK input is used to select Retransmit mode of operation. On a rising

edge of RCLK while MARK is HIGH will mark the memory location of the data

currently present on the output register, in addition placing the device in

retransmit mode. Note, there must be a minimum of 1280 bits (or 160 bytes) of

data between the write pointer and mark location. That is, 40 bits x32 for the

x40 mode, 20 bits x64 for the x20 mode, and 10 bits x128 for the x10 mode.

Also, once the MARK is set, the write pointer will not increment past the

“marked” location until the MARK is deasserted. This prevents “overwriting” of

retransmit data.

The MARK input must remain HIGH during the whole period of retransmit

mode, a falling edge of RCLK while MARK is LOW will take the device out of

retransmit mode and into normal mode. Any number of MARK locations can

be set during FIFO operation, only the last marked location taking effect. Once

a mark location has been set the write pointer cannot be incremented past this

marked location. During retransmit mode write operations to the device may

continue without hindrance.

FIRST WORD FALL THROUGH (FWFT)

During Master Reset, the state of the FWFT input determines whether the

device will operate in IDT Standard mode or First Word Fall Through (FWFT)

mode.

If, at the time of Master Reset, FWFT is LOW , then IDT Standard mode will

be selected. This mode uses the Empty Flag (EF) to indicate whether or not

there are any words present in the FIFO memory . It also uses the Full Flag

function (FF) to indicate whether or not the FIFO memory has any free space

for writing. In IDT Standard mode, every word read from the FIFO, including

the first, must be requested using the Read Enable (REN) and RCLK.

If, at the time of Master Reset, FWFT is HIGH, then FWFT mode will be

selected. This mode uses Output Ready (OR) to indicate whether or not there

is valid data at the outputs (Qn) to be read. It also uses Input Ready (IR) to

indicate whether or not the FIFO memory has any free space for writing. In the

FWFT mode, the first word written to an empty FIFO goes directly to Qn after

three RCLK rising edges, bringing REN LOW is not necessary . Subsequent

words must be accessed using the Read Enable (REN) and RCLK. Note that

FWFT mode can only be used when the device is configured to Single Data

Rate (SDR) mode.

WRITE CLOCK (WCLK)

A write cycle is initiated on the rising and/or falling edge of the WCLK input.

If the Write Single Data Rate (WSDR) pin is selected, data will be written only

on the rising edge of WCLK, provided that WEN and WCS are LOW . If the

WSDR is not selected, data will be written on both the rising and falling edge of

WCLK, provided that WEN and WCS are LOW . Data setup and hold times

must be met with respect to the LOW-to-HIGH transition of the WCLK. It is

permissible to stop the WCLK. Note that while WCLK is idle, the FF, IR, and

PAF flags will not be updated. The write and read clocks can either be

independent or coincident.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

WRITE ENABLE (WEN)

When the WEN input is LOW, data may be loaded into the FIFO RAM array

on the rising edge of every WCLK cycle if the device is not full. Data is stored

in the RAM array sequentially and independently of any ongoing read opera-

tion.

When WEN is HIGH, no new data is written in the RAM array on each

WCLK cycle.

To prevent data overflow in the IDT Standard mode, FF will go LOW,

inhibiting further write operations. Upon the completion of a valid read cycle,

FF will go HIGH, allowing a write to occur . The FF is updated by two WCLK

cycles + tSKEW after the RCLK cycle.

To prevent data overflow in the FWFT mode, IR will go HIGH, inhibiting

further write operations. Upon the completion of a valid read cycle, IR will go

LOW , allowing a write to occur. The IR flag is updated by two WCLK cycles +

tSKEW after the valid RCLK cycle.

WEN is ignored when the FIFO is full in either IDT Standard mode or

FWFT.

WRITE SINGLE DA TA RA TE (WSDR)

When the Write Single Data Rate pin is LOW , the write port will be set to

Single Data Rate mode. In this mode, all write operations are based only on

the rising edge of WCLK, provided that WEN and WCS are LOW. When

WSDR is HIGH, the read port will be set to Double Data Rate mode. In this

mode, all write operations are based on both the rising and falling edge of

WCLK, provided that WEN and WCS are LOW , on the rising edge of WCLK.

READ CLOCK (RCLK)

A read cycle is initiated on the rising and/or falling edge of the RCLK input.

If the Read Single Data Rate (RSDR) pin is selected, data will be read only on

the rising edge of RCLK, provided that REN and RCS are LOW . If the RSDR

is not selected, data will be read on both the rising and falling edge of WCLK,

provided that REN and RCS are LOW, on the rising edge of RCLK. Setup and

hold times must be met with respect to the LOW-to-HIGH transition of the

RCLK. It is permissible to stop the RCLK. Note that while RCLK is idle, the EF/

OR and PAE flags will not be updated. Write and Read Clocks can be inde-

pendent or coincident.

READ ENABLE (REN)

When Read Enable is LOW , data is loaded from the RAM array into the

output register on the rising edge of every RCLK cycle if the device is not

empty.

When the REN input is HIGH, the output register holds the previous data

and no new data is loaded into the output register . The data outputs Q0-Qn

maintain the previous data value.

In IDT Standard mode, every word accessed at Qn, including the first word

written to an empty FIFO, must be requested using REN provided that the

Read Chip Select (RCS) is LOW. When the last word has been read from the

FIFO, the Empty Flag (EF) will go LOW, inhibiting further read operations.

REN is ignored when the FIFO is empty . Once a write is performed, EF will go

HIGH allowing a read to occur . Both RCS and REN must be active LOW for

data to be read out on the rising edge of RCLK.

In FWFT mode, the first word written to an empty FIFO automatically goes

to the outputs Qn, on the third valid LOW-to-HIGH transition of RCLK + tSKEW

after the first write. REN and RCS do not need to be asserted LOW for the First

Word to fall through to the output register . All subsequent words require that a

read operation to be executed using REN and RCS. The LOW-to-HIGH

transition of RCLK after the last word has been read from the FIFO will make

Output Ready (OR) go HIGH with a true read (RCLK with REN and RCS

LOW), inhibiting further read operations. REN is ignored when the FIFO is

empty.

READ SINGLE DATA RATE (RSDR)

When the Read Single Data Rate pin is LOW , the read port will be set to

Single Data Rate mode. In this mode, all read operations are based only on

the rising edge of RCLK, provided that REN and RCS are LOW. When RSDR

is HIGH, the read port will be set to Double Data Rate mode. In this mode, all

read operations are based on both the rising and falling edge of RCLK,

provided that REN and RCS are LOW , on the rising edge of RCLK.

SERIAL CLOCK (SCLK)

The serial clock is used to load and read data in the programmable offset

registers. Data from the Serial Input (SI) can be loaded into the offset registers

on the rising edge of SCLK provided that SEN is LOW . Data can be read from

the offset registers via the Serial Output (SO) on the rising edge of SCLK

provided that SREN is LOW. The serial clock can operate at a maximum

frequency of 10MHz and its parameters are different than the FIFO system

clock.

SERIAL ENABLE (SEN)

The SEN input is an enable used for serial programming of the program-

mable offset registers. It is used in conjunction with SI and SCLK when pro-

gramming the offset registers. When SEN is LOW , data at the Serial In (SI)

input can be loaded into the offset register, one bit for each LOW-to-HIGH

transition of SCLK.

When SEN is HIGH, the offset registers retain the previous settings and no

offsets are loaded. SEN functions the same way in both IDT Standard and

FWFT modes.

SERIAL READ ENABLE (SREN)

The SREN output is an enable used for reading the value of the program-

mable offset registers. It is used in conjunction with SI and SCLK when reading

from the offset registers. When SREN is LOW , data can be read out of the offset

When SREN is HIGH, the reading of the offset registers will stop. When-

ever SREN is activated values in the offset registers are read starting from the

first location in the offset registers and not from where the last offset value was

read. SREN functions the same way in both IDT Standard and FWFT modes.

SERIAL IN (SI)

This pin acts as a serial input for loading PAE and PAF offsets into the

programmable offset registers. It is used in conjunction with the Serial Clock

(SCLK) and the Serial Enable (SEN). Data from this input can be loaded into

the offset register , one bit for each LOW-to-HIGH transition of SCLK provided

that SEN is LOW .

SERIAL OUT (SO)

This pin acts as a serial output for reading the values of the PAE and PAF

offsets in the programmable offset registers. It is used in conjunction with the

Serial Clock (SCLK) and the Serial Enable Output (SREN). Data from the

offset register can be read out using this pin, one-bit for each LOW-to-HIGH

transition of SCLK provided that SREN is LOW .

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

OUTPUT ENABLE (OE)

When Output Enable is LOW , the parallel output buffers receive data from

the output register . When OE is HIGH, the output data bus (Qn) goes into a

high-impedance state. During Master or Partial Reset the OE is the only input

that can place the output data bus into high-impedance. During reset the RCS

input can be HIGH or LOW and has no effect on the output data bus.

READ CHIP SELECT (RCS)

The Read Chip Select input provides synchronous control of the Read

output port. When RCS goes LOW , the next rising edge of RCLK causes the

Qn outputs to go to the low-impedance state. When RCS goes HIGH, the next

RCLK rising edge causes the Qn outputs to return to high-impedance. During

a Master or Partial Reset the RCS input has no effect on the Qn output bus, OE

is the only input that provides high-impedance control of the Qn outputs. If OE

is LOW, the Qn data outputs will be low-impedance regardless of RCS until the

first rising edge of RCLK after a reset is complete. Then if RCS is HIGH the

data outputs will go to high-impedance.

The RCS input does not effect the operation of the flags. For example, when

the first word is written to an empty FIFO, the EF will still go from LOW to HIGH

based on a rising edge of RCLK, regardless of the state of the RCS input.

Also, when operating the FIFO in FWFT mode the first word written to an

empty FIFO will still be clocked through to the output register based on RCLK,

regardless of the state of RCS. For this reason the user should pay extra

attention when a data word is written to an empty FIFO in FWFT mode. If RCS

is HIGH when an empty FIFO is written into, the first word will fall through to the

output register but will not be available on the Qn outputs because they are in

high-impedance. The user must take RCS active LOW to access this first word,

placing the output bus in low-impedance. REN must remain HIGH for at least

one cycle after RCS has gone LOW . A rising edge of RCLK with RCS and

REN LOW will read out the next word. Care must be taken so as not to lose the

first word written to an empty FIFO when RCS is HIGH. Refer to Figure 22,

RCS

and

REN

Read Operation (FWFT Mode). The RCS pin must also be

active (LOW) in order to perform a Retransmit. See Figure 18 for Read Cycle

and Read Chip Select Timing (IDT Standard Mode). See Figure 21 for Read

Cycle and Read Chip Select Timing (FWFT Mode).

WRITE CHIP SELECT (WCS)

The WCS disables all Write Port inputs (data only) if it is held HIGH. To

perform normal operations on the write port, the WCS must be enabled.

HSTL SELECT (HSTL)

The inputs that were listed in Table 6 can be setup to be either HSTL or

LVTTL. If HSTL is HIGH, then HSTL operation of those signals will be se-

lected. If HSTL is LOW , then L VTTL will be selected.

BUS-MATCHING (BM, IW, OW)

The pins BM, IW, and OW are used to define the input and output bus

widths. During Master Reset, the state of these pins is used to configure the

device bus sizes. See T able 1 for control settings. All flags will operate on the

word/byte size boundary as defined by the selection of bus width. See Table

7 for Bus-Matching Write to Read Ratio.

FLAG SELECT BITS (FSEL0 and FSEL1)

These pins will select the four default offset values for the PAE and PAF flags

during Master Reset. The four possible settings are listed on T able 3. Note that

the status of these inputs should not change after Master Reset.

OUTPUTS:

DA T A OUT (Q0-Q39)

(Q0 – Q39) are data outputs for 40-bit wide data, (Q0 – Q19) are data

outputs for 20-bit wide data, or (Q0 – Q9) are data outputs for 10-bit wide data.

FULL FLAG (FF/IR)

This is a dual-purpose pin. In IDT Standard mode, the Full Flag (FF) function

is selected. When the FIFO is full, FF will go LOW, inhibiting further write

operations. When FF is HIGH, the FIFO is not full. If no reads are performed

after a reset (either MRS or PRS), FF will go LOW after D writes to the FIFO

(D = 16,384 for the IDT72T4088, 32,768 for the IDT72T4098, 65,536 for the

IDT72T40108, 131,072 for the IDT72T40118. See Figure 10, Write Cycle and

Full Flag Timing (IDT Standard Mode), for the relevant timing information.

In FWFT mode, the Input Ready (IR) function is selected. IR goes LOW when

memory space is available for writing in data. When there is no longer any free

space left, IR goes HIGH, inhibiting further write operations. If no reads are

performed after a reset (either MRS or PRS), IR will go HIGH after D writes to

the FIFO (D = 16,385 for the IDT72T4088, 32,769 for the IDT72T4098, 65,537

for the IDT72T40108, 131,073 for the IDT72T40118). See Figure 19, Write

Timing (FWFT Mode), for the relevant timing information.

The IR status not only measures the contents of the FIFO memory , but also

counts the presence of a word in the output register. Thus, in FWFT mode, the

total number of writes necessary to deassert IR is one greater than needed to

assert FF in IDT Standard mode.

FF/IR is synchronous and updated on the rising edge of WCLK. FF/IR are

double register-buffered outputs.

Note, when the device is in Retransmit mode, this flag is a comparison of the

write pointer to the “marked” location. This differs from normal mode where this

flag is a comparison of the write pointer to the read pointer.

EMPTY FLAG (EF/OR)

This is a dual-purpose pin. In the IDT Standard mode, the Empty Flag (EF)

function is selected. When the FIFO is empty, EF will go LOW, inhibiting further

read operations. When EF is HIGH, the FIFO is not empty. See Figure 12, Read

Cycle, Empty Flag and First Word Latency Timing (IDT Standard Mode), for

the relevant timing information.

In FWFT mode, the Output Ready (OR) function is selected. OR goes LOW

at the same time that the first word written to an empty FIFO appears valid on

the outputs. OR stays LOW after the RCLK LOW to HIGH transition that shifts the

last word from the FIFO memory to the outputs. OR goes HIGH only with a true

read (RCLK with REN = LOW). The previous data stays at the outputs, indicating

the last word was read. Further data reads are inhibited until OR goes LOW

again. See Figure 20, Read Timing (FWFT Mode), for the relevant timing

information.

EF/OR is synchronous and updated on the rising edge of RCLK.

In IDT Standard mode, EF is a double register-buffered output. In FWFT

mode, OR is a triple register-buffered output.

PROGRAMMABLE ALMOST-FULL FLAG (PAF)

The Programmable Almost-Full flag (PAF) will go LOW when the FIFO

reaches the almost-full condition. In IDT Standard mode, if no reads are

performed after reset (MRS), PAF will go LOW after (D - m) words are written

to the FIFO. The PAF will go LOW after (16,384-m) writes for the IDT72T4088,

(32,768-m) writes for the IDT72T4098, (65,536-m) writes for the IDT72T40108,

(131,072-m) writes for the IDT72T401 18. The offset “m” is the full of fset

value. The default setting for this value is listed in Table 3.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

In FWFT mode, the PAF will go LOW after (16,385-m) writes for the

IDT72T4088, (32,769-m) writes for the IDT72T4098, (65,537-m) writes for the

IDT72T40108, (131,073-m) writes for the IDT72T40118. where m is the full

offset value. The default setting for this value is listed in Table 3.

See Figure 29, Programmable Almost-Full Flag Timing (IDT Standard and

FWFT Mode), for the relevant timing information.

Note, when the device is in Retransmit mode, this flag is a comparison of the

write pointer to the “marked” location. This differs from normal mode where this

flag is a comparison of the write pointer to the read pointer.

PROGRAMMABLE ALMOST-EMPTY FLAG (PAE)

The Programmable Almost-Empty flag (PAE) will go LOW when the FIFO

reaches the almost-empty condition. In IDT Standard mode, PAE will go LOW

when there are n words or less in the FIFO. The offset “n” is the empty offset

value. The default setting for this value is stated in the footnote of Table 3.

In FWFT mode, the PAE will go LOW when there are n+1 words or less in

the FIFO. The default setting for this value is stated in Table 3.

See Figure 30, Programmable Almost-Empty Flag Timing (IDT Standard

and FWFT Mode), for the relevant timing information.

ECHO READ CLOCK (ERCLK)

The Echo Read Clock output is provided in both HSTL and L VTTL mode,

selectable via HSTL. The ERCLK is a free-running clock output, it will always

follow the RCLK input regardless of REN and RCS.

The ERCLK output follows the RCLK input with an associated delay . This

delay provides the user with a more effective read clock source when reading

data from the Qn outputs. This is especially helpful at high speeds when

variables within the device may cause changes in the data access times.

These variations in access time maybe caused by ambient temperature, sup-

ply voltage, or device characteristics. The ERCLK output also compensates

for any trace length delays between the Qn data outputs and receiving de-

vices inputs.

Any variations effecting the data access time will also have a corresponding

effect on the ERCLK output produced by the FIFO device, therefore the

ERCLK output level transitions should always be at the same position in time

relative to the data outputs. Note, that ERCLK is guaranteed by design to be

slower than the slowest Qn, data output. Refer to Figure 4, Echo Read Clock

and Data Output Relationship, Figure 27, Echo Read Clock & Read Enable

Operation in Double Data Rate Mode and Figure 28, Echo RCLK & Echo

REN

Operation for timing information.

ECHO READ ENABLE (EREN)

The Echo Read Enable output is provided in both HSTL and LVTTL mode,

selectable via HSTL.

The EREN output is provided to be used in conjunction with the ERCLK

output and provides the reading device with a more effective scheme for

reading data from the Qn output port at high speeds. The EREN output is

controlled by internal logic that behaves as follows: The EREN output is active

LOW for the RCLK cycle that a new word is read out of the FIFO. That is, a

rising edge of RCLK will cause EREN to go active, LOW if both REN and RCS

are active, LOW and the FIFO is NOT empty.

Figure 4. Echo Read Clock and Data Output Relationship

NOTES:

1. REN is LOW.

2. tERCLK > tA, guaranteed by design.

3. Qslowest is the data output with the slowest access time, tA.

4. Time, tD is greater than zero, guaranteed by design.

5. REN = RCS = OE = 0.

5995 drw07

ERCLK

SLOWEST

(3)

RCLK

ERCLK

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

TABLE 7 — BUS-MATCHING WRITE TO READ RATIO

ONE WRITE TO ONE READ (1:1)

Configuration

WSDR RSDR BM IW OW

HHLLL

DDR Write Clock x40 Data In DDR Read Clock x40 Data Out

Positive Edge 1 D[39:0] <= L W1 Positive Edge 1 Q[39:0] <= L W1

Negative Edge 1 D[39:0] <= L W2 Negative Edge 1 Q[39:0] <= L W2

x40 DDR Input to x40 DDR Output Configuration

WSDR RSDR BM IW OW

LLLLL

SDR Write Clock x40 Data In SDR Read Clock x40 Data Out

Positive Edge 1 D[39:0] <= L W1 Positive Edge 1 Q[39:0] <= L W1

x40 SDR Input to x40 SDR Output

Configuration

WSDR RSDR BM IW OW

LHHLL

x40 SDR Input to x20 DDR Output x20 DDR Input to x40 SDR Output

ONE WRITE TO TWO READ (1:2)

Configuration

WSDR RSDR BM IW OW

HLLLL

x40 DDR Input to x40 SDR Output

Configuration

WSDR RSDR BM IW OW

HHHLL

DDR Write Clock x40 Data In DDR Read Clock x20 Data Out

Positive Edge 1 D[39:20] <= L W1 Positive Edge 1 Q[19:0] <= L W1

D[19:0] <= LW2 Negative Edge 1 Q[19:0] <= L W2

Negative Edge 1 D[39:20] <= L W3 Positive Edge 2 Q[19:0] <= L W3

D[19:0] <= LW4 Negative Edge 2 Q[19:0] <= L W4

x40 DDR Input to x20 DDR Output

SDR Write Clock x40 Data In DDR Read Clock x20 Data Out

Positive Edge 1 D[39:20] <= W1 Positive Edge 1 Q[19:0] <= W1

D[19:0] <= W2 Negative Edge 1 Q[19:0] <= W2

DDR Write Clock x20 Data In SDR Read Clock x40 Data Out

Positive Edge 1 D[19:0] <= W1 Positive Edge 1 Q[39:20] <= W1

Negative Edge 1 D[19:0] <= W2 Q[19:0] <= W2

DDR Write Clock x40 Data In SDR Read Clock x40 Data Out

Positive Edge 1 D[39:0] <= L W1 Positive Edge 1 Q[39:0] <= L W1

Negative Edge 1 D[39:0] <= LW2 Positive Edge 2 Q[39:0] <= L W1

Configuration

WSDR RSDR BM IW OW

LLHLL

x40 SDR Input to x20 SDR Output

SDR Write Clock x40 Data In SDR Read Clock x20 Data Out

Positive Edge 1 D[39:20] <= L W1 Positive Edge 1 Q[19:0] <= L W1

D[19:0] <= L W2 Positive Edge 2 Q[19:0] <= L W2

Configuration

WSDR RSDR BM IW OW

LHHLH

SDR Write Clock x40 Data In DDR Read Clock x10 Data Out

Positive Edge 1 D[39:30] <= B1 Positive Edge 1 Q[9:0] <= B1

D[29:20] <= B2 Negative Edge 1 Q[9:0] <= B2

D[19:10] <= B3 Positive Edge 2 Q[9:0] <= B3

D[9:0] <= B4 Negative Edge 2 Q[9:0] <= B4

x40 SDR Input to x10 DDR Output

Configuration

WSDR RSDR BM IW OW

HLHHL

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

TABLE 7 — BUS-MATCHING WRITE TO READ RATIO (CONTINUED)

ONE WRITE TO FOUR READ (1:4)

Configuration

WSDR RSDR BM IW OW

HLHLL

x40 DDR Input to x20 SDR Output

ONE WRITE TO EIGHT READ (1:8)

Configuration

WSDR RSDR BM IW OW

HLHLH

x40 DDR Input to x10 SDR Output

DDR Write Clock x40 Data In SDR Read Clock x20 Data Out

Positive Edge 1 D[39:20] <= L W1 Positive Edge 1 Q[19:0] <= L W1

D[19:0] <= L W2 Positive Edge 2 Q[19:0] <= L W2

Negative Edge 1 D[39:20] <= L W3 Positive Edge 3 Q[19:0] <= L W3

D[19:0] <= L W4 Positive Edge 4 Q[19:0] <= L W4

Configuration

WSDR RSDR BM IW OW

LLHLH

x40 SDR Input to x10 SDR Output

SDR Write Clock x40 Data In SDR Read Clock x10 Data Out

Positive Edge 1 D[39:30] <= B1 Positive Edge 1 Q[9:0] <= B1

D[29:20] <= B2 Positive Edge 2 Q[9:0] <= B2

D[19:10] <= B3 Positive Edge 3 Q[9:0] <= B3

D[9:0] <= B4 Positive Edge 4 Q[9:0] <= B4

Configuration

WSDR RSDR BM IW OW

HHHLH

x40 DDR Input to x10 DDR Output

DDR Write Clock x40 Data In SDR Read Clock x10 Data Out

Positive Edge 1 D[39:30] <= B1 Positive Edge 1 Q[9:0] <= B1

D[29:20]<= B2 Negaitive Edge 1 Q[9:0] <= B2

D[19:10] <= B3 Positive Edge 2 Q[9:0] <= B3

D[9:0] <= B4 Negaitive Edge 2 Q[9:0] <= B4

Negative Edge 1 D[39:30] <= B5 Positive Edge 3 Q[9:0] <= B5

D[29:20]<= B6 Negaitive Edge 3 Q[9:0] <= B6

D[19:10] <= B7 Positive Edge 4 Q[9:0] <= B7

D[9:0] <= B8 Negaitive Edge 4 Q[9:0] <= B8

DDR Write Clock x40 Data In SDR Read Clock x10 Data Out

Positive Edge 1 D[39:30] <= B1 Positive Edge 1 Q[9:0] <= B1

D[29:20]<= B2 Positive Edge 2 Q[9:0] <= B2

D[19:10] <= B3 Positive Edge 3 Q[9:0] <= B3

D[9:0] <= B4 Positive Edge 4 Q[9:0] <= B4

Negative Edge 1 D[39:30] <= B5 Positive Edge 5 Q[9:0] <= B5

D[29:20]<= B6 Positive Edge 6 Q[9:0] <= B6

D[19:10] <= B7 Positive Edge 7 Q[9:0] <= B7

D[9:0] <= B8 Positive Edge 8 Q[9:0] <= B8

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

TABLE 7 — BUS-MATCHING WRITE TO READ RATIO (CONTINUED)

TWO WRITE TO ONE READ (2:1)

Configuration

WSDR RSDR BM IW OW

LHLLL

x40 SDR Input to x40 DDR Output

SDR Write Clock x40 Data In DDR Read Clock x40 Data Out

Positive Edge 1 D[39:0] <= L W 1 Positive Edge 1 Q[39:0] <= L W1

Positive Edge 2 D[39:0] <= L W 2 Negative Edge 1 Q[39:0] <= L W2

Configuration

WSDR RSDR BM IW OW

HHHHL

x20 DDR Input to x40 DDR Output

DDR Write Clock x20 Data In DDR Read Clock x40 Data Out

Positive Edge 1 D[19:0] <= W1 Positive Edge 1 Q[39:20] <= W1

Negative Edge 1 D[19:0] <= W2 Q[19:0] <= W2

Positive Edge 2 D[19:0] <= W3 Negative Edge 1 Q[39:20] <= W3

Negative Edge 2 D[19:0] <= W4 Q[19:0] <= W4

Configuration

WSDR RSDR BM IW OW

LLHHL

x20 SDR Input to x40 SDR Output

SDR Write Clock x20 Data In SDR Read Clock x40 Data Out

Positive Edge 1 D[19:0] <= W1 Positive Edge 1 Q[39:20] <= W1

Positive Edge 2 D[19:0] <= W2 Q[19:0] <= W2

Configuration

WSDR RSDR BM IW OW

HLHHH

x10 DDR Input to x40 SDR Output

DDR Write Clock x10 Data In SDR Read Clock x40 Data Out

Positive Edge 1 D[9:0] <= B1 Positive Edge 1 Q[39:30] <= B1

Negative Edge 1 D[9:0] <= B2 Q[29:20] <= B2

Positive Edge 2 D[9:0] <= B3 Q[19:10] <= B3

Negative Edge 2 D[9:0] <= B4 Q[9:0] <= B4

FOUR WRITE TO ONE READ (4:1)

Configuration

WSDR RSDR BM IW OW

LHHHL

x20 SDR Input to x40 DDR Output

SDR Write Clock x20 Data In DDR Read Clock x40 Data Out

Positive Edge 1 D[19:0] <= W1 Positive Edge 1 Q[39:20] <= W1

Positive Edge 2 D[19:0] <= W2 Q[19:0] <= W2

Positive Edge 3 D[19:0] <= W3 Negative Edge 1 Q[39:20] <= W3

Positive Edge 4 D[19:0] <= W4 Q[19:0] <= W4

Configuration

WSDR RSDR BM IW OW

HHHHH

x10 DDR Input to x40 DDR Output

DDR Write Clock x10 Data In DDR Read Clock x40 Data Out

Positive Edge 1 D[9:0] <= B1 Positive Edge 1 Q[39:30] <= B1

Negative Edge 1 D[9:0] <= B2 Q[29:20] <= B2

Positive Edge 2 D[9:0] <= B3 Q[19:10] <= B3

Negative Edge 2 D[9:0] <= B4 Q[9:0] <= B4

Positive Edge 3 D[9:0] <= B5 Negative Edge 2 Q[39:30] <= B5

Negative Edge 3 D[9:0] <= B6 Q[29:20] <= B6

Positive Edge 4 D[9:0] <= B7 Q[19:10] <= B7

Negative Edge 4 D[9:0] <= B8 Q[9:0] <= B8

Configuration

WSDR RSDR BM IW OW

LLHHH

x10 SDR Input to x40 SDR Output

SDR Write Clock x10 Data In SDR Read Clock x40 Data Out

Positive Edge 1 D[9:0] <= B1 Positive Edge 1 Q[39:30] <= B1

Positive Edge 2 D[9:0] <= B2 Q[29:20] <= B2

Positive Edge 3 D[9:0] <= B3 Q[19:10] <= B3

Positive Edge 4 D[9:0] <= B4 Q[9:0] <= B4

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

TABLE 7 — BUS-MATCHING WRITE TO READ RATIO (CONTINUED)

EIGHT WRITE TO ONE READ (8:1)

Configuration

WSDR RSDR BM IW OW

LHHHH

x10 SDR Input to x40 DDR Output

SDR Write Clock x10 Data In DDR Read Clock x40 Data Out

Positive Edge 1 D[9:0] <= B1 Positive Edge Q[39:30] <= B1

Positive Edge 2 D[9:0] <= B2 Q[29:20] <= B2

Positive Edge 3 D[9:0] <= B3 Q[19:10] <= B3

Positive Edge 4 D[9:0] <= B4 Q[9:0] <= B4

Positive Edge 5 D[9:0] <= B5 Negative Edge Q[39:30] <= B5

Positive Edge 6 D[9:0] <= B6 Q[29:20] <= B6

Positive Edge 7 D[9:0] <= B7 Q[19:10] <= B7

Positive Edge 8 D[9:0] <= B8 Q[9:0] <= B8

TABLE 8 — TSKEW MEASUREMENT

Data Port Status Flags TSKEW Measurement

Configuration

DDR Input EF & PAE Negative Edge WCLK to

t o Positive Edge RCLK

DDR Output FF & PAF Negative Edge RCLK to

Positive Edge WCLK

DDR Input EF & PAE Negative Edge WCLK to

t o Positive Edge RCLK

SDR Output FF & PAF Positive Edge RCLK to

Positive Edge WCLK

SDR Input EF & PAE Positive Edge WCLK to

t o Positive Edge RCLK

DDR Output FF & PAF Negative Edge RCLK to

Positive Edge WCLK

SDR Input EF & PAE Positive Edge WCLK to

t o Positive Edge RCLK

SDR Output FF & PAF Positive Edge RCLK to

Positive Edge WCLK

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 5. Standard JTAG Timing

SYSTEM INTERFACE PARAMETERS

Parameter Symbol Test

Conditions Min. Max. Units

JTAG Clock Input Period tTCK - 100 - ns

JTAG Clock HIGH tTCKHIGH -40-ns

JTAG Clock Low tTCKLOW -40-ns

JTAG Clock Rise Time tTCKRISE --5

(1) ns

JTAG Clock Fall Time tTCKFALL --5

(1) ns

JTAG Reset tRST -50-ns

JTAG Reset Recovery tRSR -50-ns

JTAG

AC ELECTRICAL CHARACTERISTICS

(vcc = 2.5V ± 5%; Tcase = 0°C to +85°C)

IDT72T4088

IDT72T4098

IDT72T40108

IDT72T40118

Parameter Symbol Test Conditions Min. Max. Units

Data Output tDO(1) -20ns

Data Output Hold tDOH(1) 0-ns

Data Input tDS trise=3ns 10 - ns

tDH tfall=3ns 10 -

NOTE:

1. 50pf loading on external output signals.

JTAG TIMING SPECIFICATION

NOTE:

1. Guaranteed by design.

TDO

TDI/

TMS

TCK

TRST

Notes to diagram:

t1 =

TCKLOW

t2 =

TCKHIGH

t3 =

TCKFALL

t4 = t

TCKRISE

t5 =

tRST

(reset pulse width)

t6 = tRSR (reset recovery)

5995 drw08

t1t2

TCK

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

JTAG INTERFACE

Five additional pins (TDI, TDO, TMS, TCK and TRST) are provided to

support the JTAG boundary scan interface. The IDT72T4088/72T4098/

72T40108/72T40118 incorporates the necessary tap controller and modified

pad cells to implement the JTAG facility.

Note that IDT provides appropriate Boundary Scan Description Language

program files for these devices.

The Standard JTAG interface consists of four basic elements:

•Test Access Port (TAP)

•TAP controller

•Instruction Register (IR)

•Data Register Port (DR)

The following sections provide a brief description of each element. For a

complete description refer to the IEEE Standard Test Access Port Specification

(IEEE Std. 1149.1-1990).

The Figure below shows the standard Boundary-Scan Architecture

Figure 6. Boundary Scan Architecture

TEST ACCESS PORT (TAP)

The Tap interface is a general-purpose port that provides access to the

internal of the processor. It consists of four input ports (TCLK, TMS, TDI, TRST)

and one output port (TDO).

THE TAP CONTROLLER

The Tap controller is a synchronous finite state machine that responds to

TMS and TCLK signals to generate clock and control signals to the Instruction

and Data Registers for capture and update of data.

TAP

Cont-

roller

Mux

DeviceID Reg.

Boundary Scan Reg.

Bypass Reg.

clkDR, ShiftDR

UpdateDR

TDO

TDI

TMS

TCLK

TRST

clklR, ShiftlR

UpdatelR

Instruction Register

Instruction Decode

Control Signals

5995 drw09

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 7. TAP Controller State Diagram

Test-Logic

Reset

Run-Test/

Idle

Select-

DR-Scan

Select-

IR-Scan

111

Capture-IR

Capture-DR

EXit1-DR

Pause-DR

Exit2-DR

Update-DR

Exit1-IR

Exit2-IR

Update-IR

5995 drw10

Shift-DR

Shift-IR

Pause-IR

Input = TMS

Refer to the IEEE Standard Test Access Port Specification (IEEE Std.

1149.1) for the full state diagram

All state transitions within the TAP controller occur at the rising edge of the

TCLK pulse. The TMS signal level (0 or 1) determines the state progression

that occurs on each TCLK rising edge. The TAP controller takes precedence

over the FIFO memory and must be reset after power up of the device. See

TRST description for more details on TAP controller reset.

Test-Logic-Reset All test logic is disabled in this controller state enabling the

normal operation of the IC. The TAP controller state machine is designed in such

a way that, no matter what the initial state of the controller is, the Test-Logic-Reset

state can be entered by holding TMS at high and pulsing TCK five times. This

is the reason why the Test Reset (TRST) pin is optional.

Run-Test-Idle In this controller state, the test logic in the IC is active only if

certain instructions are present. For example, if an instruction activates the self

test, then it will be executed when the controller enters this state. The test logic

in the IC is idles otherwise.

Select-DR-Scan This is a controller state where the decision to enter the

Data Path or the Select-IR-Scan state is made.

Select-IR-Scan This is a controller state where the decision to enter the

Instruction Path is made. The Controller can return to the Test-Logic-Reset state

other wise.

Capture-IR In this controller state, the shift register bank in the Instruction

last two significant bits are always required to be “01”.

Shift-IR In this controller state, the instruction register gets connected

between TDI and TDO, and the captured pattern gets shifted on each rising edge

of TCK. The instruction available on the TDI pin is also shifted in to the instruction

Exit1-IR This is a controller state where a decision to enter either the Pause-

IR state or Update-IR state is made.

Pause-IR This state is provided in order to allow the shifting of instruction

Exit2-DR This is a controller state where a decision to enter either the Shift-

IR state or Update-IR state is made.

Update-IR In this controller state, the instruction in the instruction register is

latched in to the latch bank of the Instruction Register on every falling edge of

TCK. This instruction also becomes the current instruction once it is latched.

Capture-DR In this controller state, the data is parallel loaded in to the data

registers selected by the current instruction on the rising edge of TCK.

Shift-DR, Exit1-DR, Pause-DR, Exit2-DR and Update-DR These

controller states are similar to the Shift-IR, Exit1-IR, Pause-IR, Exit2-IR and

Update-IR states in the Instruction path.

NOTES:

1. Five consecutive TCK cycles with TMS = 1 will reset the TAP.

2. TAP controller does not automatically reset upon power-up. The user must provide a reset to the TAP controller (either by TRST or TMS).

3. TAP controller must be reset before normal FIFO operations can begin.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

THE INSTRUCTION REGISTER

The Instruction register allows an instruction to be shifted in serially into the

processor at the rising edge of TCLK.

The Instruction is used to select the test to be performed, or the test data

at the completion of the shifting process when the TAP controller is at Update-

IR state.

The instruction register must contain 4 bit instruction register-based cells

which can hold instruction data. These mandatory cells are located nearest the

serial outputs they are the least significant bits.

TEST DATA REGISTER

The Test Data register contains three test data registers: the Bypass, the

Boundary Scan register and Device ID register.

These registers are connected in parallel between a common serial input

and a common serial data output.

The following sections provide a brief description of each element. For a

complete description, refer to the IEEE Standard Test Access Port Specification

(IEEE Std. 1149.1-1990).

TEST BYPASS REGISTER

The register is used to allow test data to flow through the device from TDI

to TDO. It contains a single stage shift register for a minimum length in serial path.

When the bypass register is selected by an instruction, the shift register stage

is set to a logic zero on the rising edge of TCLK when the TAP controller is in

the Capture-DR state.

The operation of the bypass register should not have any effect on the

operation of the device in response to the BYPASS instruction.

THE BOUNDARY-SCAN REGISTER

The Boundary Scan Register allows serial data TDI be loaded in to or read

out of the processor input/output ports. The Boundary Scan Register is a part

of the IEEE 1149.1-1990 Standard JTAG Implementation.

THE DEVICE IDENTIFICATION REGISTER

The Device Identification Register is a Read Only 32-bit register used to

specify the manufacturer, part number and version of the processor to be

determined through the TAP in response to the IDCODE instruction.

IDT JEDEC ID number is 0xB3. This translates to 0x33 when the parity

is dropped in the 11-bit Manufacturer ID field.

For the IDT72T4088/72T4098/72T40108/72T40118, the Part Number

field contains the following values:

IDT72T4088/4098/40108/40118 JTAG Device Identification Register

31(MSB) 28 27 12 11 1 0(LSB)

V ersion (4 bits) Part Number (16-bit) Manufacturer ID (1 1-bit)

0X0 0X33 1

JTAG INSTRUCTION REGISTER

The Instruction register allows instruction to be serially input into the device

when the TAP controller is in the Shift-IR state. The instruction is decoded to

perform the following:

•Select test data registers that may operate while the instruction is

current. The other test data registers should not interfere with chip

operation and the selected data register.

•Define the serial test data register path that is used to shift data between

TDI and TDO during data register scanning.

The Instruction Register is a 4 bit field (i.e.IR3, IR2, IR1, IR0) to decode 16

different possible instructions. Instructions are decoded as follows.

Hex Instruction Function

Value

0x02 IDCODE Select Chip Identification data register

0x01 SAMPLE/PRELOAD Select Boundary Scan Register

0x03 HI-IMPEDANCE JTAG

0x0F BYPASS Select Bypass Register

Table 8. JTAG Instruction Register Decoding

The following sections provide a brief description of each instruction. For

a complete description refer to the IEEE Standard Test Access Port Specification

(IEEE Std. 1149.1-1990).

IDCODE

The optional IDCODE instruction allows the IC to remain in its functional mode

and selects the optional device identification register to be connected between

TDI and TDO. The device identification register is a 32-bit shift register containing

information regarding the IC manufacturer, device type, and version code.

Accessing the device identification register does not interfere with the operation

of the IC. Also, access to the device identification register should be immediately

available, via a TAP data-scan operation, after power-up of the IC or after the

TAP has been reset using the optional TRST pin or by otherwise moving to the

Test-Logic-Reset state.

SAMPLE/PRELOAD

The required SAMPLE/PRELOAD instruction allows the IC to remain in a

normal functional mode and selects the boundary-scan register to be connected

between TDI and TDO. During this instruction, the boundary-scan register can

be accessed via a date scan operation, to take a sample of the functional data

entering and leaving the IC.

HIGH-IMPEDANCE

The optional High-Impedance instruction sets all outputs (including two-state

as well as three-state types) of an IC to a disabled (high-impedance) state and

selects the one-bit bypass register to be connected between TDI and TDO.

During this instruction, data can be shifted through the bypass register from TDI

to TDO without affecting the condition of the IC outputs.

BYPASS

The required BYPASS instruction allows the IC to remain in a normal

functional mode and selects the one-bit bypass register to be connected

between TDI and TDO. The BYPASS instruction allows serial data to be

transferred through the IC from TDI to TDO without affecting the operation of

the IC.

Device Part# Field

IDT72T4088 04A3

IDT72T4098 04A2

IDT72T40108 04A1

IDT72T40118 04A0

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 8. Master Reset Timing

NOTES:

1 . During Master Reset the High-Impedance control of the Qn data outputs is provided by OE only, RCS can be HIGH or LOW until the first rising edge of RCLK after Master Reset

is complete.

2. The status of these pins are latched in when the Master Reset pulse is LOW.

5995 drw11

SEN

tRSF

OE = HIGH

OE = LOW

PAE

PAF

Q0 - Qn

tRSF

EF/OR

FF/IR

tRSF

tRSF If FWFT = HIGH, OR = HIGH

If FWFT = LOW, EF = LOW

If FWFT = LOW, FF = HIGH

If FWFT = HIGH, IR = LOW

tRSS

SREN

tRSS

tRS

MRS

tRSR

REN

tRSS

FWFT(2)

tRSR

WEN

FSEL0(2),

FSEL1

OW(2),

IW, BM

tRSS

tHRSS

HSTL(2)

WSDR(2)

tRSRtRSS

RSDR(2)

tRSRtRSS

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 9. Partial Reset Timing

NOTE:

1 . During Partial Reset the High-Impedance control of the Qn data outputs is provided by OE only, RCS can be HIGH or LOW until the first rising edge of RCLK after Master Reset

is complete.

PRS

RSR

REN

RSS

5995 drw12

RSR

WEN

SEN

RSF

OE = HIGH

OE = LOW

PAE

PAF

- Q

RSF

EF/OR

FF/IR

RSF

RSF If FWFT = HIGH, OR = HIGH

If FWFT = LOW, EF = LOW

If FWFT = LOW, FF = HIGH

If FWFT = HIGH, IR = LOW

RSS

SREN

RSS

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 10. Write Cycle and Full Flag Timing (IDT Standard Mode)

NOTES:

1. tSKEW1 is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that FF will go HIGH (after one WCLK cycle plus tWFF). If the time between the

rising edge of the RCLK and the rising edge of the WCLK is less than tSKEW1, then the FF deassertion may be delayed one extra WCLK cycle.

2. OE = LOW, EF = HIGH.

3. WCS = LOW.

4. WCLK must be free running for FF to update.

D0 - D39

WEN

RCLK

REN

tENH t

ENH

Q0 - Q39 DATA READ NEXT DATA READ

SKEW1

(1)

5995 drw13

WCLK

NO WRITE

1212

NO WRITE

WFF

tENS t

ENS

(1)

tDS

CLK1

CLKH1

RCS

tENS

tRCSLZ

WFF

SKEW1

CLKL1

X+1

WFF

tDS t

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 11. Write Cycle and Full Flag Timing in Double Data Rate Mode (IDT Standard Mode)

NOTES:

1. tSKEW2 is the minimum time between a falling RCLK edge and a rising WCLK edge to guarantee that FF will go HIGH (after one WCLK cycle plus tWFF). If the time between the falling edge of the RCLK and the rising edge of WCLK

is less than tSKEW2, then FF deassertion may be delayed one extra WCLK cycle.

2. OE = LOW, EF = HIGH.

3. WCS = LOW, RCS = LOW, WSDR = HIGH and RSDR = HIGH.

4. WCLK must be free running for FF to update.

Data Read

-Q39

5995 drw14

NO WRITE

D39

RCLK

WCLK

WEN

CLKL2

CLKH2

CLK2

SKEW2

(1)

SKEW2

(1)

REN

NO WRITE

Dx+1

Dx+2 Dx+3

WFF

ENH

ENS

ENH

ENS

Data in Output Register Next Data Read Next Data

Next Data Read

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 12. Read Cycle, Output Enable, Empty Flag and First Data Word Latency (IDT Standard Mode)

NOTES:

1. tSKEW1 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that EF will go HIGH (after one RCLK cycle plus tREF). If the time between the

rising edge of WCLK and the rising edge of RCLK is less than tSKEW1, then EF deassertion may be delayed one extra RCLK cycle.

2. First data word latency = tSKEW1 + 1*TRCLK + tREF.

3. RCS is LOW.

4. RCLK must be free running for EF to update.

5995 drw15

D0 - D39

NO OPERATION

RCLK

REN

CLK1

ENH

REF

OLZ

Q0 - Q39

WCLK

(1)

SKEW1

WEN

ENS

ENH

OLZ

NO OPERATION

LAST WORD D

ENS

ENH

OHZ

LAST WORD

REF

ENH

ENS

REF

ENS

ENH

WCS

WCSS

WCS

CLKH1

CLKL1

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 13. Read Cycle, Output Enable, Empty Flag and First Data Word Latency in Double Data Rate Mode (IDT Standard Mode)

NOTES:

1. tSKEW2 is the minimum time between a falling WCLK edge and a rising RCLK edge to guarantee that EF will go HIGH (after one RCLK cycle plus tREF). If the time between the falling edge of WCLK and the rising edge of RCLK

is less than tSKEW2, then EF deassertion may be delayed one extra RCLK cycle.

2. REN = LOW.

3. First data word latency = tSKEW1 + 1*tRCLK + tREF.

4. RCS = LOW, WSDR = HIGH and RSDR = HIGH.

5. RCLK must be free running for EF to update.

tOLZ

REF

OHZ

OLZ

WCLK

WEN

-D

5995 drw16

ENS

ENH

REF

RCLK

SKEW2

(1)

CLK2

CLKH2

WCS

WCSS

WCSH

-1

NO Read NO Read NO Read NO Read

CLKL2

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 14. Read Cycle, Empty Flag and First Data Word Latency in x40DDR to x10SDR with Bus-Matching and Rate-Matching (IDT Standard Mode)

RCLK

WEN

REN

WCS

ENS

SKEW2(1)

D0-D39

W0 - W3

Q0-Q9

WCLK t

ENH

twc

WCSS

W4 - W7

REF

ENS

W0 W1 W2

W3 W4 W5 W6 W7

ENH

REF

Previous Data in Ouput Register

5995 drw17

NOTES:

is less than tSKEW2, then EF deassertion may be delayed one extra RCLK cycle.

2. REN = LOW.

3. First data word latency = tSKEW1 + 1*tRCLK + tREF.

4. RCS = LOW, WSDR = HIGH and RSDR = HIGH.

5. RCLK must be free running for EF to update.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 15. Read Cycle and Empty Flag in x20SDR to x40DDR with Bus-Matching and Rate-Matching (IDT Standard Mode)

NOTES:

1. tSKEW1 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that EF will go HIGH (after one RCLK cycle plus tREF). If the time between the rising edge of WCLK and the rising edge of RCLK is

less than tSKEW1, then EF deassertion may be delayed one extra RCLK cycle.

2. OE = LOW.

3. First data word latency = tSKEW1 + 1*tRCLK + tREF.

4. RCS = LOW, WCS = LOW, WSDR = LOW and RSDR = HIGH.

5. RCLK must be free running for EF to update.

SKEW

(1)

WCLK

RCLK

REN

WEN

REF

-D

5995 drw18

REF

Last Word Last 40-bit Word

ENS

ENH

ENS

-W

CLK2

CLKH2

CLKL2

Previous Data

ENH

NO Read

-W

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 16. Write Cycle and Full Flag Timing in x20DDR to x40SDR with Bus-Matching and Rate-Matching (IDT Standard Mode)

WCLK

WEN

RCS

ENS

SKEW1(1)

-Q

RCLK

ENH

ENS

WFF

-D

REN

RCSLZ

WFF

SKEW1(1)

ENS

ENH

WFF

CLK2

CLKH2

CLKL2

NO WRITE

WFF

DATA READ NEXT DATA READ

Wx Wx+1 Wx+2 Wx+3

5995 drw19

NOTES:

1. tSKEW1 is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that FF will go HIGH (after one WCLK cycle plus tWFF). If the time between the rising edge of the RCLK and the rising edge of the

WCLK is less than tSKEW1, then the FF deassertion may be delayed one extra WCLK cycle.

2. LD = HIGH, OE = LOW, EF = HIGH.

3. WCS = LOW.

4. WCLK must be free running for FF to update.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 17. Write Cycle and Full Flag in x40SDR to x20DDR with Bus-Matching and Rate-Matching (IDT Standard Mode)

WCLK

WEN

RCS

ENS

Q0-Q19

RCLK

ENH

ENS

WFF

D0-D39

REN

RCSLZ

ENS

ENH

CLK1

NO WRITE

WFF

DATA READ NEXT DATA READ

Wx Wx+2 Wx+3

Wx+1

CLKH1

WFF

SKEW2(1)

WFF

ENS

RCSHZ

DATA

READ

NEXT DATA

READ

5995 drw20

SKEW2(1)

NOTES:

is less than tSKEW2, then FF deassertion may be delayed one extra WCLK cycle.

2. OE = LOW, EF = HIGH.

3. WCS = LOW, RCS = LOW, WSDR = HIGH and RSDR = HIGH.

4. WCLK must be free running for FF to update.

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 18. Read Cycle and Read Chip Select (IDT Standard Mode)

NOTES:

1. tSKEW1 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that EF will go HIGH (after one RCLK cycle plus tREF). If the time between the

rising edge of WCLK and the rising edge of RCLK is less than tSKEW1, then EF deassertion may be delayed one extra RCLK cycle.

2. First data word latency = tSKEW1 + 1*TRCLK + tREF.

3. OE is LOW.

4. RCLK must be free running for EF to update.

RCLK

REN

5995 drw21

RCS

Q0 - Qn

WCLK

WEN

ENS

LAST DATA

ENS

REF

RCSLZ

LAST DATA-1

RCSHZ

RCSLZ

RCSHZ

SKEW1

(1)

ENH

ENS

ENH

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 19. Write Timing (FWFT Mode)

NOTES:

1. tSKEW1 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that OR will go LOW after two RCLK cycles plus tREF. If the time between the rising edge of WCLK and the rising edge of RCLK

is less than tSKEW1, then OR assertion may be delayed one extra RCLK cycle.

2. tSKEW2 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that PAE will go HIGH after one RCLK cycle plus tPAES. If the time between the rising edge of WCLK and the rising edge of RCLK

is less than tSKEW2, then the PAE deassertion may be delayed one extra RCLK cycle.

3. OE = LOW

4. n = PAE offset, m = PAF offset and D = maximum FIFO depth.

5. D = 16,385 for IDT72T4088, 32,769 for IDT72T4098, 65,537 for IDT72T40108, 131,073 for IDT72T40118.

6. First data word latency = tSKEW1 + 2*TRCLK + tREF.

[n +2]

[D-m-1]

[D-m-2]

[D-1]

[n+3]

[n+4]

[D-m]

[D-m+1]

WCLK

WEN

D0 - Dn

RCLK

SKEW1

(1)

REN

Q0 - Qn

PAF

PAE

SKEW2

REF

PAES

PAFS

WFF

[D-m+2]

ENH

5995 drw22

PREVIOUS DATA IN OUTPUT REGISTER

(2)

123

D-1

2+1

][

D-1

][

D-1

][

ENS

RCS

RCSLZ

ENS

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 20. Read Timing (FWFT Mode)

NOTES:

is less than tSKEW1, then OR assertion may be delayed one extra RCLK cycle.

is less than tSKEW2, then the PAE deassertion may be delayed one extra RCLK cycle.

3. OE = LOW

4. n = PAE offset, m = PAF offset and D = maximum FIFO depth.

5. D = 16,385 for IDT72T4088, 32,769 for IDT72T4098, 65,537 for IDT72T40108, 131,073 for IDT72T40118.

6. First data word latency = tSKEW1 + 2*TRCLK + tREF.

WCLK 12

WEN

D0 - Dn

RCLK

ENS

REN

Q0 - Qn

PAF

PAE

m+2

[m+3]

OHZ

SKEW1

ENH

PAFS

WFF

ENS

SKEW2

5995 drw23

PAES

[D-n]

[D-n-1]

REF

[D-1]

[D-n+1]

[m+4]

[D-n+2]

(1) (2)

ENS

D-1 + 1

][

2D-1 + 2

][

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 21. Read Cycle and Read Chip Select Timing (FWFT Mode)

NOTES:

1. tSKEW1 is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that IR will go LOW after one WCLK cycle plus tWFF. If the time between the rising edge of RCLK and the rising edge of WCLK is

less than tSKEW1, then the IR assertion may be delayed one extra WCLK cycle.

2. tSKEW2 is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that PAF will go HIGH after one WCLK cycle plus tPAFS. If the time between the rising edge of RCLK and the rising edge of WCLK

is less than tSKEW2, then the PAF deassertion may be delayed one extra WCLK cycle.

3. n = PAE Offset, m = PAF offset and D = maximum FIFO depth.

4. D = 16,385 for IDT72T4088, 32,769 for IDT72T4098, 65,537 for IDT72T40108, 131,073 for IDT72T40118.

5. OE = LOW.

6. RCLK must be free running for EF to update.

WCLK

WEN

D0 - Dn

RCLK

REN

Q0 - Qn

PAF

PAE

m+2

[m+3]

RCSHZ

SKEW1

ENH

PAFS

WFF

ENS

RCS

SKEW2

5995 drw24

PAES

[D-n]

[D-n-1]

[D-1]

[D-n+1]

[m+4]

[D-n+2]

(1) (2)

ENS

RCSLZ

ENS

REF

D-1

+ 1

][

D-1

+ 2

][

ENH

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 22 .

RCS

and

REN

Read Operation (FWFT Mode)

NOTES:

1. It is very important that the REN be held HIGH for at least one cycle after RCS has gone LOW. If REN goes LOW on the same cycle as RCS or earlier, then Word, W1 will be lost, Word, W2 will be read on the output when the

bus goes to LOW-Z.

2. The 1st Word will fall through to the output register regardless of REN and RCS. However, subsequent reads require that both REN and RCS be active, LOW.

3. RCS functions similarly to OE, when RCS is HIGH the read pointer will not increment.

WCLK

RCLK

REN

WEN

ENS

ENH

ENS

ENH

ENS

REF

RCS

RCSLZ

W1 W2

RCSHZ

RCSLZ

SKEW

ENS

ENH

1st Word falls through to

O/P register on this cycle

5995 drw25

HIGH-Z

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 23 . Retransmit from MARK in Double Data Rate Mode (IDT Standard Mode)

NOTES:

1. Retransmit setup is complete when EF returns HIGH.

2. OE = LOW;RCS = LOW.

3. RT must be HIGH when reading from FIFO.

4. Once MARK is set, the write pointer will not increment past the ‘marked’ location, preventing overwrites of Retransmit data.

5. Before a “MARK” can be set there must be at least 160 bytes of data between the Write Pointer and Read Pointer locations. (160 bytes = 16 words = 8 long words).

6. RCLK must be free running for EF to update.

7. A transition in the PAE flag may not occur until one RCLK cycle later than shown.

8. In DDR mode the MARK function will “MARK” words only on even word boundaries (i.e. Rising edge of RCLK).

Q0-Qn

WCLK

RCLK

REN

PAF

tCLKL2

tCLKH2

tCLK2

WMK

MARK

tAtAtA

WMK+2

tAtA

WMK+3 WMK+4 WMK+5 WMK+6 WMK+n

PAE

tENS

tENH

tREF tREF

tENS

tPAES(7)

tAtA

WMK WMK+1 WMK+2

tSKEW2

tPAFS

5995 drw26

tENH

tENS tENS

WMK+1

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 24. Retransmit from Mark (FWFT Mode)

NOTES:

1. Retransmit setup is complete when OR returns LOW.

2. OE = LOW;RCS = LOW.

3. RT must be HIGH when reading from FIFO.

4. Once MARK is set, the write pointer will not increment past the ‘marked’ location, preventing overwrites of Retransmit data.

5. Before a “MARK” can be set there must be at least 160 bytes of data between the Write Pointer and Read Pointer locations. (160 bytes = 16 words = 8 long words).

6. RCLK must be free running for EF to update.

7. A transition in the PAE flag may not occur until one RCLK cycle later than shown.

REF

ENS

ENH

5995 drw27

ENS

MK-1

WCLK

RCLK

REN

PAF

PAE

PAFS

REF

WEN

ENS

MK+1

MK+n

MK+1

MK+2

ENS

MARK

ENH

ENS

PAES(7)

SKEW2

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 25. Loading of Programmable Flag Registers (IDT Standard and FWFT Modes)

NOTE:

1 . In SDR mode, X = 14 for the IDT72T4088, X = 15 for the IDT72T4098, X = 16 for the IDT72T40108, X = 17 for the IDT72T40118.

2 . In DDR mode, X = 13 for the IDT72T4088, X = 14 for the IDT72T4098, X = 15 for the IDT72T70108, X = 16 for the IDT72T40118.

SCLK

SEN

5995 drw28

EMPTY OFFSET FULL OFFSET

BIT X

(1)

SENS

SDS

SENH

BIT X

(1)

BIT 1

ENH

SDH

SCLK

SCKH

SCKL

BIT 1

Figure 26. Reading of Programmable Flag Registers (IDT Standard and FWFT Modes)

NOTE:

1 . In SDR mode, X = 14 for the IDT72T4088, X = 15 for the IDT72T4098, X = 16 for the IDT72T40108, X = 17 for the IDT72T40118.

2 . In DDR mode, X = 13 for the IDT72T4088, X = 14 for the IDT72T4098, X = 15 for the IDT72T40108, X = 16 for the IDT72T40118.

3. Offset register values are always read starting from the first location in the offset register upon initiating SREN.

SCLK

SREN

5995 drw29

BIT 0

EMPTY OFFSET

FULL OFFSET

BIT X

(1)

SENS

SOA

SENH

BIT X

(1)

ENH

SOA

SCLK

SCKH

SCKL

BIT 0

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 27. Echo Read Clock & Read Enable Operation in Double Data Rate Mode (IDT Standard Mode Only)

NOTES:

1. The EREN output is “or gated” to RCS and REN and will follow these inputs provided that the FIFO is not empty. If the FIFO is empty, EREN will go HIGH to indicate that there is no new word available.

2. The EREN output is synchronous to RCLK.

3. OE = LOW.

4. The truth table for EREN is shown below:

RCLK

REN

EREN

ERCLK

RCS

ENS

REF

ERCLK

ENH

ENS

ENH

CLKEN

OLZ

CLKEN

OLZ

WD-10 WD-9 WD-8 WD-6 WD-5 WD-4 WD-3 WD-2 Last Word WD

5995 drw30

CLKEN

WD-7 WD-6

WD-1

ENS

NO Read NO Read

RCLK EF RCS REN EREN

↑1000

↑1011

↑1101

↑1111

↑0XX1

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

Figure 28. Echo RCLK and Echo

REN

Operation (FWFT Mode Only)

NOTE:

1. The O/P Register is the internal output register. Its contents are available on the Qn output bus only when RCS and OE are both active, LOW, that is the bus is not in High-

Impedance state.

2. OE is LOW.

Cycle:

a&b. At this point the FIFO is empty, OR is HIGH.

RCS and REN are both disabled, the output bus is High-Impedance.

c. Word Wn+1 falls through to the output register, OR goes active, LOW.

RCS is HIGH, therefore the Qn outputs are High-Impedance. EREN goes LOW to indicate that a new word has been placed on the output register.

d. EREN goes HIGH, no new word has been placed on the output register on this cycle.

e. No Operation.

f. RCS is LOW on this cycle, therefore the Qn outputs go to Low-Impedance and the contents of the output register (Wn+1) are made available.

NOTE: In FWFT mode is important to take RCS active LOW at least one cycle ahead of REN, this ensures the word (Wn+1) currently in the output register is made

available for at least one cycle.

g. REN goes active LOW, this reads out the second word, Wn+2.

EREN goes active LOW to indicate a new word has been placed into the output register.

h. Word Wn+3 is read out, EREN remains active, LOW indicating a new word has been read out.

NOTE: Wn+3 is the last word in the FIFO.

i. This is the next enabled read after the last word, Wn+3 has been read out. OR flag goes HIGH and EREN goes HIGH to indicate that there is no new word available.

3. OE is LOW.

4. The truth table for EREN is shown below:

O/P

Reg.

REF

5995 drw31

RCSLZ

REN t

ENS

ENH

RCS

ENS

RCLK abcdefghi

Wn+1

WCLK

WEN

D0 - Dn

SKEW1

ENS

ENH

Wn+2 Wn+3

ERCLK

EREN

CLKEN

Wn+1 Wn+2 Wn+3

REF

Wn+1 Wn+2 Wn+3

Wn Last Word

ERCLK

HIGH-Z

RCLK OR RCS REN EREN

↑0000

↑0011

↑0101

↑0111

↑1XX1

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

NOTES:

1. m = PAF offset.

2. D = maximum FIFO Depth.

In IDT Standard Mode:

D=16,384 for the IDT72T4088, 32,768 for the IDT72T4098, 65,536 for the IDT72T40108, 131,072 for the IDT72T40118.

In FWFT Mode: D=16,385 for the IDT72T4088, 32,769 for the IDT72T4098, 65,537 for the IDT72T40108, 131,073 for the IDT72T40118.

3. PAF is asserted and updated on the rising edge of WCLK only.

4. tSKEW3 is the minimum time between a rising RCLK edge and a rising WCLK edge to guarantee that PAF will go HIGH (after one WCLK cycle plus tPAFS). If the time between the

rising edge of RCLK and the rising edge of WCLK is less than tSKEW3, then the PAF deassertion time may be delayed one extra WCLK cycle.

5. RCS = LOW.

Figure 29. Programmable Almost-Full Flag Timing (IDT Standard and FWFT Modes)

NOTES:

1 . n = PAE offset.

2. For IDT Standard Mode.

3. For FWFT Mode.

4. PAE is asserted and updated on the rising edge of RCLK only.

tSKEW3 is the minimum time between a rising WCLK edge and a rising RCLK edge to guarantee that PAE will go HIGH (after one RCLK cycle plus tPAES). If the time between the

rising edge of WCLK and the rising edge of RCLK is less than tSKEW3, then the PAE deassertion may be delayed one extra RCLK cycle.

5. PAE is asserted and updated on the rising edge of RCLK only.

6. RCS = LOW.

Figure 30. Programmable Almost-Empty Flag Timing (IDT Standard and FWFT Modes)

WCLK

WEN

PAF

RCLK

REN

5995 drw32

1212

D-(m+1) words

in FIFO(2)

D - m words in FIFO(2)

D - (m +1) words in FIFO(2)

tENH

tENS

tPAFS

tENS tENH

tCLKL1

tSKEW3

(3)

tPAFS

tCLKH1

WCLK

WEN

PAE

RCLK

12 12

REN

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n + 1 words in FIFO

(2)

n + 2 words in FIFO

(3)

ENS

SKEW3

(4)

ENH

PAES

n words in FIFO

(2)

n + 1 words in FIFO

(3)

PAES

n words in FIFO

(2)

n + 1 words in FIFO

(3)

ENS

ENH

CLKH1

CLKL1

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

OPTIONAL CONFIGURATIONS

WIDTH EXPANSION CONFIGURATION

Word width may be increased simply by connecting together the control

signals of multiple devices. Status flags can be detected from any one device.

The exceptions are the EF and FF functions in IDT Standard mode and the IR

and OR functions in FWFT mode. Because of variations in skew between RCLK

and WCLK, it is possible for EF/FF deassertion and IR/OR assertion to vary

by one cycle between FIFOs. In IDT Standard mode, such problems can be

avoided by creating composite flags, that is, ANDing EF of every FIFO, and

separately ANDing FF of every FIFO. In FWFT mode, composite flags can

be created by ORing OR of every FIFO, and separately ORing IR of every

FIFO.

Figure 31 demonstrates a width expansion using two IDT72T4088/

72T4098/72T40108/72T40118 devices. D0 - D40 from each device form a 80-

bit wide input bus and Q0-Q39 from each device form a 80-bit wide output bus.

Any word width can be attained by adding additional IDT72T4088/72T4098/

72T40108/72T40118 devices.

NOTES:

1. Use an AND gate in IDT Standard mode, an OR gate in FWFT mode.

2. Do not connect any output control signals directly together.

3. FIFO #1 and FIFO #2 must be the same depth, but may be different word widths.

Figure 31. Block Diagram of 16,384 x 80, 32,768 x 80, 65,536 x 80, 131,072 x 80 Width Expansion

WRITE CLOCK (WCLK)

m + n mn

MASTER RESET (MRS)

READ CLOCK (RCLK)

DATA OUT

nm + n

WRITE ENABLE (WEN)

FULL FLAG/INPUT READY (FF/IR)

PROGRAMMABLE (PAF)

PROGRAMMABLE (PAE)

EMPTY FLAG/OUTPUT READY (EF/OR) #2

OUTPUT ENABLE (OE)

READ ENABLE (REN)

IDT

72T4088

72T4098

72T40108

72T40118

EMPTY FLAG/OUTPUT READY (EF/OR) #1

PARTIAL RESET (PRS)

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FULL FLAG/INPUT READY (FF/IR) #2

FIRST WORD FALL THROUGH

(FWFT)

RETRANSMIT (RT)

FIFO

GATE

(1)

GATE

(1)

D0 - Dm

DATA IN

Dm+1 - Dn

- Qm

m+1 - Qn

FIFO

IDT

72T4088

72T4098

72T40108

72T40118

READ CHIP SELECT (RCS)

SERIAL CLOCK (SCLK)

COMMERCIAL AND INDUSTRIAL

TEMPERATURE RANGES

IDT72T4088/98/108/118 2.5V HIGH-SPEED TeraSync™ DDR/SDR FIFO 40-BIT

CONFIGURATION 16,384 x 40, 32,768 x 40, 65,536 x 40 and 131,072 x 40

DEPTH EXPANSION CONFIGURATION IN SINGLE DATA RATE

(FWFT MODE ONLY)

The IDT72T4088 can easily be adapted to applications requiring depths

greater than 16,384, 32,768 for the IDT72T4098, 65,536 for the IDT72T40108,

131,072 for the IDT72T40118 with an 40-bit bus width. In FWFT mode, the

FIFOs can be connected in series (the data outputs of one FIFO connected to

the data inputs of the next) with no external logic necessary. The resulting

configuration provides a total depth equivalent to the sum of the depths

associated with each single FIFO. Figure 32 shows a depth expansion using

two IDT72T4088/72T4098/72T40108/72T40118 devices.

Care should be taken to select FWFT mode during Master Reset for all FIFOs

in the depth expansion configuration. Also, the devices must be operating in

Single Data Rate mode since that is the only mode available in FWFT. The first

word written to an empty configuration will pass from one FIFO to the next ("ripple

down") until it finally appears at the outputs of the last FIFO in the chain – no read

operation is necessary but the RCLK of each FIFO must be free-running. Each

time the data word appears at the outputs of one FIFO, that device's OR line goes

LOW, enabling a write to the next FIFO in line.

For an empty expansion configuration, the amount of time it takes for OR of

the last FIFO in the chain to go LOW (i.e. valid data to appear on the last FIFO's

outputs) after a word has been written to the first FIFO is the sum of the delays

for each individual FIFO:

(N – 1)*(4*transfer clock) + 3*TRCLK

where N is the number of FIFOs in the expansion and TRCLK is the RCLK period.

Note that extra cycles should be added for the possibility that the tSKEW1

specification is not met between WCLK and transfer clock, or RCLK and transfer

clock, for the OR flag.

The "ripple down" delay is only noticeable for the first word written to an empty

depth expansion configuration. There will be no delay evident for subsequent

words written to the configuration.

The first free location created by reading from a full depth expansion

configuration will "bubble up" from the last FIFO to the previous one until it finally

moves into the first FIFO of the chain. Each time a free location is created in one

FIFO of the chain, that FIFO's IR line goes LOW, enabling the preceding FIFO

to write a word to fill it.

For a full expansion configuration, the amount of time it takes for IR of the first

FIFO in the chain to go LOW after a word has been read from the last FIFO is

the sum of the delays for each individual FIFO:

(N – 1)*(3*transfer clock) + 2 TWCLK

where N is the number of FIFOs in the expansion and TWCLK is the WCLK

period. Note that extra cycles should be added for the possibility that the tSKEW1

specification is not met between RCLK and transfer clock, or WCLK and transfer

clock, for the IR flag.

The Transfer Clock line should be tied to either WCLK or RCLK, whichever

is faster. Both these actions result in data moving, as quickly as possible, to the

end of the chain and free locations to the beginning of the chain.

Figure 32. Block Diagram of 32,768 x 40, 65,536 x 40, 131,072 x 40, 262,144 x 40 Depth Expansion in Single Data Rate Mode

INPUT READY

WRITE ENABLE

WRITE CLOCK

WEN

WCLK

DATA IN

RCLK READ CLOCK

RCLK

REN

OE OUTPUT ENABLE

OUTPUT READY

GND

WEN

WCLK

REN

READ ENABLE

DATA OUT

TRANSFER CLOCK

5995 drw35

n n

FWFT FWFT

FWFT

IDT

72T4088

72T4098

72T40108

72T40118

RCS READ CHIP SELECT

RCS

IDT

72T4088

72T4098

72T40108

72T40118

CORPORATE HEADQUARTERS for SALES: for Tech Support:

2975 Stender Way 800-345-7015 or 408-727-6116 408-330-1753

Santa Clara, CA 95054 fax: 408-492-8674 email: FI FOhelp@i dt.com

www.idt.com

ORDERING INFORMATION

Plastic Ball Grid Array (PBGA, BB208-1)

Commercial (0°C to +70°C)

Industrial (-40°C to +85°C)

Low Power

5995 drw36

Commercial Only

Commercial and Industrial

Commercial Only

6-7

IDT XXXXX

Device Type

Power

Speed

Package

Process /

Temperature

Range

BLANK

I(1)

72T4088 16,384 x 40  2.5V High-Speed TeraSync

DDR/SDR FIFO

72T4098 32,768 x 40  2.5V High-Speed TeraSync

DDR/SDR FIFO

72T40108 65,536 x 40  2.5V High-Speed TeraSync

DDR/SDR FIFO

72T40118 131,072 x 40  2.5V High-Speed TeraSync

DDR/SDR FIFO

Clock Cycle Time (t

CLK

)

Speed in Nanoseconds

NOTE:

1. Industrial temperature range product is available for 6-7ns as a standard product. All other speed grades are available by special order.

DATASHEET DOCUMENT HISTORY

03/01/2002 pgs. 1, 4, 6, 8, 9, and 23.

04/08/2002 pgs. 1, 8, 9, 11, 33-37, 42, 46-48, and 51.

04/24/2002 pgs. 19, and 28.

05/24/2002 pgs. 6-9, and 12.

11/21/2002 pgs. 1, and 10.

02/11/2003 pgs. 7, 8, and 27.

03/20/2003 pgs. 25, 27, 28, and 44.

12/17/2003 pgs. 10, 31-34, 36-38, 44, and 49.