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©2007 Integrated Device Technology, Inc.
OCTOBER 2008
DSC-3821/05
ZBT and Zero Bus Turnaround are trademarks of Integrated Device Technology, Inc. and the architecture is supported by Micron Technology and Motorola Inc.
Pin Description Summary
Description
The IDT71V546 is a 3.3V high-speed 4,718,592-bit (4.5 Megabit)
synchronous SRAM organized as 128K x 36 bits. It is designed to
eliminate dead bus cycles when turning the bus around between reads
and writes, or writes and reads. Thus it has been given the name ZBTTM,
or Zero Bus Turn-around.
Address and control signals are applied to the SRAM during one
Features
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◆128K x 36 memory configuration, pipelined outputs
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◆Supports high performance system speed - 133 MHz
(4.2 ns Clock-to-Data Access)
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◆ZBTTM Feature - No dead cycles between write and read
cycles
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◆Internally synchronized registered outputs eliminate the
need to control OE
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◆Single R/W (READ/WRITE) control pin
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◆Positive clock-edge triggered address, data, and control
signal registers for fully pipelined applications
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◆4-word burst capability (interleaved or linear)
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◆Individual byte write (BW1 - BW4) control (May tie active)
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◆Three chip enables for simple depth expansion
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◆Single 3.3V power supply (±5%)
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◆Packaged in a JEDEC standard 100-pin TQFP package
clock cycle, and two cycles later its associated data cycle occurs, be it
read or write.
The IDT71V546 contains data I/O, address and control signal regis-
ters. Output enable is the only asynchronous signal and can be used to
disable the outputs at any given time.
A Clock Enable (CEN) pin allows operation of the IDT71V546 to be
suspended as long as necessary. All synchronous inputs are ignored
when CEN is high and the internal device registers will hold their previous
values.
There are three chip enable pins (CE1, CE2, CE2) that allow the user
to deselect the device when desired. If any one of these three is not active
when ADV/LD is low, no new memory operation can be initiated and any
burst that was in progress is stopped. However, any pending data
transfers (reads or writes) will be completed. The data bus will tri-state two
cycles after the chip is deselected or a write initiated.
The IDT71V546 has an on-chip burst counter. In the burst mode, the
IDT71V546 can provide four cycles of data for a single address presented
to the SRAM. The order of the burst sequence is defined by the LBO input
pin. The LBO pin selects between linear and interleaved burst sequence.
The ADV/LD signal is used to load a new external address (ADV/LD =
LOW) or increment the internal burst counter (ADV/LD = HIGH).
The IDT71V546 SRAM utilizes IDT's high-performance, high-volume
3.3V CMOS process, and is packaged in a JEDEC standard 14mm x
20mm 100- pin thin plastic quad flatpack (TQFP) for high board density.
IDT71V546S/XS
128K x 36, 3.3V Synchronous
SRAM with ZBT™™
™™
™ Feature,
Burst Counter and Pipelined Outputs
A
0
- A
16
Address Inputs Input Synchronous
CE
1
, CE
2
, CE
2
Three Chip Enables Input Synchronous
OE Output Enable Input Asynchronous
R/WRe ad / Write Sig nal Inp ut S ync hro no us
CEN Clock Enable Input Synchronous
BW
1
, BW
2
, BW
3
, BW
4
Indiv idual By te Write Selects Input Sync hronous
CLK Clock Input N/A
ADV/LD Advance Burst Address / Load New Address Input Synchronous
LBO Linear / Interleaved Burst Order Input Static
I/O
0
- I/O
31
, I/O
P1
- I/O
P4
Data Inp ut/Outp ut I/O Sync hronous
V
DD
3.3V Po we r Sup ply Static
V
SS
Ground Supply Static
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