Future Technology Devices International Ltd.
Copyright © Future Technology Devices International Ltd. 2005
FT245R USB FIFO I.C.
Incorporating FTDIChip-ID™ Security Dongle
The FT245R is the latest device to be added to FTDI’s range of USB FIFO interface Integrated Circuit Devices.
The FT245R is a USB to parallel FIFO interface, with the new FTDIChip-ID™ security dongle feature. In addition,
asynchronous and synchronous bit bang interface modes are available. USB to parallel designs using the FT245R
have been further simplified by fully integrating the external EEPROM, clock circuit and USB resistors onto the device.
The FT245R adds a new function compared with its predecessors, effectively making it a “2-in-1” chip for some
application areas. A unique number (the FTDIChip-ID™) is burnt into the device during manufacture and is readable
over USB, thus forming the basis of a security dongle which can be used to protect customer application software
from being copied.
The FT245R is available in Pb-free (RoHS compliant) compact 28-Lead SSOP and QFN-32 packages.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 2
Single chip USB to parallel FIFO bidirectional data
transfer interface.
Entire USB protocol handled on the chip - No
USB-specific firmware programming required.
Simple interface to MCU / PLD / FPGA logic with
simple 4-wire handshake interface.
Data transfer rate to 1 Megabyte / second - D2XX
Direct Drivers.
Data transfer rate to 300 kilobyte / second - VCP
Drivers.
256 byte receive buffer and 128 byte transmit
buffer utilising buffer smoothing technology to allow
for high data throughput.
FTDI’s royalty-free VCP and D2XX drivers
eliminate the requirement for USB driver
development in most cases.
New USB FTDIChip-ID™ feature.
FIFO receive and transmit buffers for high data
throughput.
Adjustable receive buffer timeout.
Synchronous and asynchronous bit bang mode
interface options with RD# and WR# strobes allow
the data bus to be used as a general purpose I/O
port.
Integrated 1024 Bit internal EEPROM for storing
USB VID, PID, serial number and product
description strings.
Device supplied preprogrammed with unique USB
serial number.
Support for USB suspend / resume through
PWREN# pin and Wake Up pin function.
In-built support for event characters.
Support for bus powered, self powered, and high-
power bus powered USB configurations.
Integrated 3.3V level converter for USB I/O .
Integrated level converter on FIFO interface and
control pins for interfacing to 5V - 1.8V Logic.
True 5V / 3.3V / 2.8V / 1.8V CMOS drive output
and TTL input.
High I/O pin output drive option.
Integrated USB resistors.
Integrated power-on-reset circuit.
Fully integrated clock - no external crystal,
oscillator, or resonator required.
Fully integrated AVCC supply filtering - No separate
AVCC pin and no external R-C filter required.
USB bulk transfer mode.
3.3V to 5.25V Single Supply Operation.
Low operating and USB suspend current.
Low USB bandwidth consumption.
UHCI / OHCI / EHCI host controller compatible
USB 2.0 Full Speed compatible.
-40°C to 85°C extended operating temperature
range.
Available in compact Pb-free 28 Pin SSOP and
QFN-32 packages (both RoHS compliant).
1. Features
1.1 Hardware Features
Royalty-Free VIRTUAL COM PORT
(VCP) DRIVERS for...
Windows 98, 98SE, ME, 2000, Server 2003, XP.
Windows Vista / Longhorn*
Windows XP 64-bit.*
Windows XP Embedded.
Windows CE.NET 4.2 & 5.0
MAC OS 8 / 9, OS-X
Linux 2.4 and greater
Royalty-Free D2XX Direct Drivers
(USB Drivers + DLL S/W Interface)
Windows 98, 98SE, ME, 2000, Server 2003, XP.
Windows Vista / Longhorn*
Windows XP 64-bit.*
Windows XP Embedded.
Windows CE.NET 4.2 & 5.0
Linux 2.4 and greater
1.2 Driver Support
The drivers listed above are all available to download for free from the FTDI website. Various 3rd Party Drivers are
also available for various other operating systems - see the FTDI website for details.
* Currently Under Development. Contact FTDI for availability.
Upgrading Legacy Peripherals to USB
Cellular and Cordless Phone USB data transfer
cables and interfaces
Interfacing MCU / PLD / FPGA based designs to
USB
USB Audio and Low Bandwidth Video data transfer
PDA to USB data transfer
USB Smart Card Readers
USB Instrumentation
USB Industrial Control
USB MP3 Player Interface
USB FLASH Card Reader / Writers
Set Top Box PC - USB interface
USB Digital Camera Interface
USB Hardware Modems
USB Wireless Modems
USB Bar Code Readers
USB Software / Hardware Encryption Dongles
1.3 Typical Applications
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 3
2. Enhancements
2.1 Device Enhancements and Key Features
This section summarises the enhancements and the key features of the FT245R device. For further details, consult
the device pin-out description and functional description sections.
Integrated Clock Circuit - Previous generations of FTDI’s USB to parallel FIFO interface devices required an external
crystal or ceramic resonator. The clock circuit has now been integrated onto the device meaning that no crystal or
ceramic resonator is required. However, if required, an external 12MHz crystal can be used as the clock source.
Integrated EEPROM - Previous generations of FTDI’s USB to parallel FIFO interface devices required an external
EEPROM if the device were to use USB Vendor ID (VID), Product ID (PID), serial number and product description
strings other than the default values in the device itself. This external EEPROM has now been integrated onto the
FT245R chip meaning that all designs have the option to change the product description strings. A user area of the
internal EEPROM is available for storing additional data. The internal EEPROM is programmable in circuit, over USB
without any additional voltage requirement.
Preprogrammed EEPROM - The FT245R is supplied with its internal EEPROM preprogrammed with a serial number
which is unique to each individual device. This, in most cases, will remove the need to program the device EEPROM.
Integrated USB Resistors - Previous generations of FTDI’s USB to parallel FIFO interface devices required two
external series resistors on the USBDP and USBDM lines, and a 1.5 kΩ pull up resistor on USBDP. These three
resistors have now been integrated onto the device.
Integrated AVCC Filtering - Previous generations of FTDI’s USB to parallel FIFO interface devices had a separate
AVCC pin - the supply to the internal PLL. This pin required an external R-C filter. The separate AVCC pin is now
connected internally to VCC, and the filter has now been integrated onto the chip.
Less External Components - Integration of the crystal, EEPROM, USB resistors, and AVCC filter will substantially
reduce the bill of materials cost for USB interface designs using the FT245R compared to its FT245BM predecessor.
Transmit and Receive Buffer Smoothing - The FT245R’s 256 byte receive buffer and 128 byte transmit buffer utilise
new buffer smoothing technology to allow for high data throughput.
Enhanced Asynchronous Bit Bang Mode with RD# and WR# Strobes - The FT245R supports FTDI’s BM chip bit
bang mode. In bit bang mode, the eight parallel FIFO data bus lines can be switched from the regular interface mode
to an 8-bit general purpose I/O port. Data packets can be sent to the device and they will be sequentially sent to the
interface at a rate controlled by an internal timer (equivalent to the baud rate prescaler). With the FT245R device this
mode has been enhanced so that the internal RD# and WR# strobes are now brought out of the device which can be
used to allow external logic to be clocked by accesses to the bit bang I/O bus. This option will be described more fully
in a separate application note
Synchronous Bit Bang Mode - Synchronous bit bang mode differs from asynchronous bit bang mode in that the
interface pins are only read when the device is written to. Thus making it easier for the controlling program to measure
the response to an output stimulus as the data returned is synchronous to the output data. The feature was previously
seen in FTDI’s FT2232C device. This option will be described more fully in a separate application note.
Lower Supply Voltage - Previous generations of the chip required 5V supply on the VCC pin. The FT245R will work
with a Vcc supply in the range 3.3V - 5V. Bus powered designs would still take their supply from the 5V on the USB
bus, but for self powered designs where only 3.3V is available, and there is no 5V supply, there is no longer any need
for an additional external regulator.
Integrated Level Converter on FIFO Interface and Control Signals - VCCIO pin supply can be from 1.8V to 5V.
Connecting the VCCIO pin to 1.8V, 2.8V, or 3.3V allows the device to directly interface to 1.8V, 2.8V or 3.3V and other
logic families without the need for external level converter I.C.s
5V / 3.3V / 2.8V / 1.8V Logic Interface - The FT245R provides true CMOS Drive Outputs and TTL level Inputs.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 4
Integrated Power-On-Reset (POR) Circuit- The device incorporates an internal POR function. A RESET# pin is
available in order to allow external logic to reset the FT245R where required. However, for many applications the
RESET# pin can be left unconnected, or pulled up to VCCIO.
Wake Up Function - If USB is in suspend mode, and remote wake up has been enabled in the internal EEPROM (it is
enabled by default), the RXF# pin becomes an input. Strobing this pin low will cause the FT245R to request a resume
from suspend on the USB bus. Normally this can be used to wake up the host PC from suspend
Lower Operating and Suspend Current - The device operating supply current has been further reduced to 15mA,
and the suspend current has been reduced to around 70μA. This allows a greater margin for peripherals to meet the
USB suspend current limit of 500μA.
Low USB Bandwidth Consumption - The operation of the USB interface to the FT245R has been designed to use
as little as possible of the total USB bandwidth available from the USB host controller.
High Output Drive Option - The parallel FIFO interface and the four FIFO handshake pins can be made to drive
out at three times the standard signal drive level thus allowing multiple devices to be driven, or devices that require a
greater signal drive strength to be interfaced to the FT245R. This option is configured in the internal EEPROM.
Power Management Control for USB Bus Powered, High Current Designs- The PWREN# signal can be used to
directly drive a transistor or P-Channel MOSFET in applications where power switching of external circuitry is required.
An option in the internal EEPROM makes the device gently pull down on its FIFO interface lines when the power
is shut off (PWREN# is high). In this mode any residual voltage on external circuitry is bled to GND when power is
removed, thus ensuring that external circuitry controlled by PWREN# resets reliably when power is restored.
FTDIChip-ID™ - Each FT245R is assigned a unique number which is burnt into the device at manufacture. This ID
number cannot be reprogrammed by product manufacturers or end-users. This allows the possibility of using FT245R
based dongles for software licensing. Further to this, a renewable license scheme can be implemented based on the
FTDIChip-ID™ number when encrypted with other information. This encrypted number can be stored in the user area
of the FT245R internal EEPROM, and can be decrypted, then compared with the protected FTDIChip-ID™ to verify
that a license is valid. Web based applications can be used to maintain product licensing this way. An application note
describing this feature is available separately from the FTDI website.
Improved EMI Performance - The reduced operating current and improved on-chip VCC decoupling significantly
improves the ease of PCB design requirements in order to meet FCC, CE and other EMI related specifications.
Programmable FIFO TX Buffer Timeout - The FIFO TX buffer timeout is used to flush remaining data from the
receive buffer. This timeout defaults to 16ms, but is programmable over USB in 1ms increments from 1ms to 255ms,
thus allowing the device to be optimised for protocols that require fast response times from short data packets.
Extended Operating Temperature Range - The FT232R operates over an extended temperature range of -40º to
+85º C thus allowing the device to be used in automotive and industrial applications.
New Package Options - The FT245R is available in two packages - a compact 28 pin SSOP ( FT245RL) and an
ultra-compact 5mm x 5mm pinless QFN-32 package ( FT245RQ). Both packages are lead ( Pb ) free, and use a
‘green’ compound. Both packages are fully compliant with European Union directive 2002/95/EC.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 5
3. Block Diagram
3.1 Block Diagram (Simplified)
Figure 1 - FT245R Block Diagram
3.2 Functional Block Descriptions
3.3V LDO Regulator - The 3.3V LDO Regulator generates the 3.3V reference voltage for driving the USB transceiver
cell output buffers. It requires an external decoupling capacitor to be attached to the 3V3OUT regulator output pin. It
also provides 3.3V power to the 1.5kΩ internal pull up resistor on USBDP. The main function of this block is to power
the USB Transceiver and the Reset Generator Cells, rather than to power external logic. However, external circuitry
requiring 3.3V nominal at a current of around 50mA could also draw its power from the 3V3OUT pin if required.
USB Transceiver - The USB Transceiver Cell provides the USB 1.1 / USB 2.0 full-speed physical interface to the USB
cable. The output drivers provide 3.3V level slew rate control signalling, whilst a differential receiver and two single
ended receivers provide USB data in, SEO and USB Reset condition detection. This Cell also incorporates internal
USB series resistors on the USB data lines, and a 1.5kΩ pull up resistor on USBDP.
USB DPLL - The USB DPLL cell locks on to the incoming NRZI USB data and provides separate recovered clock and
data signals to the SIE block.
Internal 12MHz Oscillator - The Internal 12MHz Oscillator cell generates a 12MHz reference clock input to the x4
Clock multiplier. The 12MHz Oscillator is also used as the reference clock for the SIE, USB Protocol Engine and FIFO
controller blocks
Clock Multiplier - The Clock Multiplier takes the 12MHz input from the Oscillator Cell and generates the 48MHz clock
reference used for the USB DPLL block.
Serial Interface Engine (SIE) - The Serial Interface Engine (SIE) block performs the Parallel to Serial and Serial to
Parallel conversion of the USB data. In accordance to the USB 2.0 specification, it performs bit stuffing / un-stuffing
and CRC5 / CRC16 generation / checking on the USB data stream.
Clock
Multiplier
Serial Interface
Engine
( SIE )
USB
Protocol Engine
3.3 Volt
LDO
Regulator
USB
Transceiver
with
Integrated
Series
Resistors
and 1.5K
Pull-up
USB DPLL
Internal
12MHz
Oscillator
48MHz
OCSI
(optional)
OSCO
(optional)
USBDP
USBDM
3V3OUT
VCC
D0
D1
D2
D3
D4
D5
D6
D7
RD#
RXF#
TXE#
RESET#
TEST
GND
RESET
GENERATOR
3V3OUT
WR
FIFO TX Buffer
128 bytes
FIFO RX Buffer
256 bytes
Internal
EEPROM
To USB Transceiver Cell
PWREN#
To USB
Transceiver
Cell
VCCIO
FIFO Controller
with
Programmable
High Drive
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 6
USB Protocol Engine - The USB Protocol Engine manages the data stream from the device USB control endpoint. It
handles the low level USB protocol (Chapter 9) requests generated by the USB host controller and the commands for
controlling the functional parameters of the FIFO.
FIFO TX Buffer (128 byte) - Data written into the FIFO using the WR pin is stored in the FIFO TX (transmit) Buffer.
The USB host controller removes data from the FIFO TX Buffer by sending a USB request for data from the device
data In endpoint.
FIFO RX Buffer (256 byte) - Data sent from the USB host controller to the FIFO via the USB data Out endpoint is
stored in the FIFO RX (receive) buffer and is removed from the buffer by reading the contents of the FIFO using the
RD# pin.
FIFO Controller - The FIFO controller handles the transfer of data between the external FIFO interface pins (D0 - D7)
and the FIFO transmit and receive buffers. A new feature, which is enabled in the internal EEPROM allows high signal
drive strength on the FIFO parallel data bus and handshake control pins.
RESET Generator - The integrated Reset Generator Cell provides a reliable power-on reset to the device internal
circuitry on power up. A RESET# input is provided to allow other devices to reset the FT245R. RESET# can be tied
to VCCIO or left unconnected, unless there is a requirement to reset the FT245R device from external logic or an
external reset generator I.C.
Internal EEPROM - The internal EEPROM in the FT245R can be used to store USB Vendor ID (VID), Product ID
(PID), device serial number, product description string, and various other USB configuration descriptors. The device is
supplied with the internal EEPROM settings preprogrammed as described in Section 10.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 7
4. Device Pin Out and Signal Descriptions
4.1 28-LD SSOP Package
USBDP
USBDM
3V3OUT
GND
RESET#
VCC
GND
NC
AGND
TEST
OSCI
OSCO
TXE#
RXF#
D0
D2
D1
D4
VCCIO
D7
GND
NC
D5
D6
D3
PWREN#
RD#
WR
FT245RL
YYXX-A
1
14 15
28
FTDI
Figure 2 - 28 Pin SSOP Package Pin Out
Figure 3 - 28 Pin SSOP Package Pin Out (Schematic Symbol)
FT245RL
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
25 7 18 21 26
3V3OUT
VCCIO
4
17
NC
RESET#
NC
24
19
8
D0
D1
D2
D3
D4
D5
D6
D7
1
5
3
11
2
9
10
6
RXF#
WR
RD#
TXE#
23
22
13
14
20
16
15 USBDP
USBDM
VCC
OSCI
27
OSCO
28
PWREN# 12
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 8
4.2 SSOP-28 Package Signal Descriptions
Table 1 - SSOP Package Pin Out Description
Pin No. Name Type Description
USB Interface Group
15 USBDP I/O USB Data Signal Plus, incorporating internal series resistor and 1.5kΩ pull up resistor to 3.3V
16 USBDM I/O USB Data Signal Minus, incorporating internal series resistor.
Power and Ground Group
4 VCCIO PWR +1.8V to +5.25V supply to the FIFO Interface and Control group pins (1...3, 5, 6, 9...14, 22, 23). In USB bus
powered designs connect to 3V3OUT to drive out at 3.3V levels, or connect to VCC to drive out at 5V CMOS
level. This pin can also be supplied with an external 1.8V - 2.8V supply in order to drive out at lower levels. It
should be noted that in this case this supply should originate from the same source as the supply to Vcc. This
means that in bus powered designs a regulator which is supplied by the 5V on the USB bus should be used.
7, 18, 21 GND PWR Device ground supply pins
17 3V3OUT Output 3.3V output from integrated L.D.O. regulator. This pin should be decoupled to ground using a 100nF capacitor.
The prime purpose of this pin is to provide the internal 3.3V supply to the USB transceiver cell and the internal
1.5kΩ pull up resistor on USBDP. Up to 50mA can be drawn from this pin to power external logic if required.
This pin can also be used to supply the FT245R’s VCCIO pin.
20 VCC PWR 3.3V to 5.25V supply to the device core.
25 AGND PWR Device analog ground supply for internal clock multiplier
Miscellaneous Signal Group
8, 24 NC NC No internal connection.
19 RESET# Input Can be used by an external device to reset the FT245R. If not required can be left unconnected or pulled up
to VCCIO.
26 TEST Input Puts the device into I.C. test mode. Must be grounded for normal operation.
27 OSCI Input Input to 12MHz Oscillator Cell. Optional - Can be left unconnected for normal operation. *
28 OSCO Output Output from 12MHz Oscillator Cell. Optional - Can be left unconnected for normal operation if internal oscilla-
tor is used.*
FIFO Interface and Control Group
1 D0 I/O FIFO Data Bus Bit 0**
2 D4 I/O FIFO Data Bus Bit 4**
3 D2 I/O FIFO Data Bus Bit 2**
5 D1 I/O FIFO Data Bus Bit 1**
6 D7 I/O FIFO Data Bus Bit 7**
9 D5 I/O FIFO Data Bus Bit 5**
10 D6 I/O FIFO Data Bus Bit 6**
11 D3 I/O FIFO Data Bus Bit 3**
12 PWREN# Output Goes low after the device is configured by USB, then high during USB suspend. Can be used to control power
to external logic P-Channel logic level MOSFET switch. Enable the interface pull-down option when using the
PWREN# pin in this way.
13 RD# Input Enables the current FIFO data byte on D0...D7 when low. Fetched the next FIFO data byte (if available) from
the receive FIFO buffer when RD# goes from high to low. See Section 4.5 for timing diagram. **
14 WR Input Writes the data byte on the D0...D7 pins into the transmit FIFO buffer when WR goes from high to low. See
Section 4.5 for timing diagram. **
22 TXE# Output When high, do not write data into the FIFO. When low, data can be written into the FIFO by strobing WR high,
then low. During reset this signal pin is tri-state, but pulled up to VCCIO via an internal 200kΩ resistor. See
Section 4.5 for timing diagram.
23 RXF# Output When high, do not read data from the FIFO. When low, there is data available in the FIFO which can be read
by strobing RD# low, then high again. During reset this signal pin is tri-state, but pulled up to VCCIO via an
internal 200kΩ resistor. See Section 4.5 for timing diagram.
If the Remote Wakeup option is enabled in the internal EEPROM, during USB suspend mode (PWREN# = 1)
RXF# becomes an input which can be used to wake up the USB host from suspend mode. Strobing the pin
low will cause the device to request a resume on the USB bus.
*Contact FTDI Support for details of how to use an external crystal, ceramic resonator, or oscillator with the FT245R.
** When used in Input Mode, these pins are pulled to VCCIO via internal 200kΩ resistors. These can be programmed
to gently pull low during USB suspend ( PWREN# = “1” ) by setting this option in the internal EEPROM.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 9
4.3 QFN-32 Package
Figure 4 - QFN-32 Package Pin Out
FT245RQ
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
24 4 17 20 26
3V3OUT
VCCIO
1
16
NC
RESET#
NC
23
18
13
D0
D1
D2
D3
D4
D5
D6
D6
30
2
32
8
31
6
7
3
RXF#
WR
RD#
TXE#
22
21
10
11
19
15
14 USBDP
USBDM
VCC
OSCI
27
OSCO
28
PWREN# 9
NC
12
NC
5
NC
29
NC
25
Figure 5 - QFN-32 Package Pin Out (Schematic Symbol)
FT245RQ
32 25
24
17
16
9
8
1
YYXX-A
18
9
1
2
3
4
5
6
7
8
10111213141516
17
19
20
21
22
23
24
25 26 27 28 29 30 31 32
USBDP
USBDM
3V3OUT
RESET#
VCC
NC
AGND
TEST
OSCI
OSCO
TXE#
RXF#
D0
D2
D1
D4
VCCIO
D7
GND
NC
D5
D6
D3
PWREN#
RD#
WR
GND
GND
NC
NC
NC
NC
FTDI
TOP
BOTTOM
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 10
4.4 QFN-32 Package Signal Descriptions
Table 2 - QFN Package Pin Out Description
Pin No. Name Type Description
USB Interface Group
14 USBDP I/O USB Data Signal Plus, incorporating internal series resistor and 1.5kΩ pull up resistor to 3.3V
15 USBDM I/O USB Data Signal Minus, incorporating internal series resistor.
Power and Ground Group
1 VCCIO PWR +1.8V to +5.25V supply to FIFO Interface and Control group pins (2,3, 6, ...,11, 21, 22, 30,..32). In USB bus
powered designs connect to 3V3OUT to drive out at 3.3V levels, or connect to VCC to drive out at 5V CMOS
level. This pin can also be supplied with an external 1.8V - 2.8V supply in order to drive out at lower levels. It
should be noted that in this case this supply should originate from the same source as the supply to Vcc. This
means that in bus powered designs a regulator which is supplied by the 5V on the USB bus should be used.
4, 17, 20 GND PWR Device ground supply pins
16 3V3OUT Output 3.3V output from integrated L.D.O. regulator. This pin should be decoupled to ground using a 100nF capacitor.
The prime purpose of this pin is to provide the internal 3.3V supply to the USB transceiver cell and the internal
1.5kΩ pull up resistor on USBDP. Up to 50mA can be drawn from this pin to power external logic if required.
This pin can also be used to supply the FT245R’s VCCIO pin.
19 VCC PWR 3.3V to 5.25V supply to the device core.
24 AGND PWR Device analog ground supply for internal clock multiplier
Miscellaneous Signal Group
5, 12, 13,
23, 25, 29
NC NC No internal connection.
18 RESET# Input Can be used by an external device to reset the FT245R. If not required can be left unconnected or pulled up
to VCCIO.
26 TEST Input Puts the device into I.C. test mode. Must be grounded for normal operation.
27 OSCI Input Input to 12MHz Oscillator Cell. Optional - Can be left unconnected for normal operation. *
28 OSCO Output Output from 12MHz Oscillator Cell. Optional - Can be left unconnected for normal operation if internal oscilla-
tor is used. *
FIFO Interface and Control Group
30 D0 I/O FIFO Data Bus Bit 0**
31 D4 I/O FIFO Data Bus Bit 4**
32 D2 I/O FIFO Data Bus Bit 2**
2 D1 I/O FIFO Data Bus Bit 1**
3 D7 I/O FIFO Data Bus Bit 7**
6 D5 I/O FIFO Data Bus Bit 5**
7 D6 I/O FIFO Data Bus Bit 6**
8 D3 I/O FIFO Data Bus Bit 3**
9 PWREN# Output Goes low after the device is configured by USB, then high during USB suspend. Can be used to control power
to external logic P-Channel logic level MOSFET switch. Enable the interface pull-down option when using the
PWREN# pin in this way.
10 RD# Input Enables the current FIFO data byte on D0...D7 when low. Fetched the next FIFO data byte (if available) from
the receive FIFO buffer when RD# goes from high to low. See Section 4.5 for timing diagram. **
11 WR Input Writes the data byte on the D0...D7 pins into the transmit FIFO buffer when WR goes from high to low. See
Section 4.5 for timing diagram. **
21 TXE# Output When high, do not write data into the FIFO. When low, data can be written into the FIFO by strobing WR high,
then low. During reset this signal pin is tri-state, but pulled up to VCCIO via an internal 200kΩ resistor. See
Section 4.5 for timing diagram.
22 RXF# Output When high, do not read data from the FIFO. When low, there is data available in the FIFO which can be read
by strobing RD# low, then high again. During reset this signal pin is tri-state, but pulled up to VCCIO via an
internal 200kΩ resistor. See Section 4.5 for timing diagram.
If the Remote Wakeup option is enabled in the internal EEPROM, during USB suspend mode (PWREN# = 1)
RXF# becomes an input which can be used to wake up the host from suspend mode. Strobing the pin low will
cause the device to request a resume on the USB bus.
*Contact FTDI Support for details of how to use an external crystal, ceramic resonator, or oscillator with the FT245R.
** When used in Input Mode, these pins are pulled to VCCIO via internal 200kΩ resistors. These can be programmed
to gently pull low during USB suspend ( PWREN# = “1” ) by setting this option in the internal EEPROM.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 11
4.5 FT245R FIFO Timing Diagrams
Figure 6 - FIFO Read Cycle
RXF#
RD#
D[7...0]
T3
T1
T5
T6
T2
T4
Valid Data
Table 3 - FIFO Read Cycle Timings
Time Description Min Max Unit
T1 RD Active Pulse Width 50 ns
T2 RD to RD Pre-Charge Time 50 + T6 ns
T3 RD Active to Valid Data* 20 50 ns
T4 Valid Data Hold Time from RD Inactive* 0 ns
T5 RD Inactive to RXF# 0 25 ns
T6 RXF Inactive After RD Cycle 80 ns
* Load = 30pF
Figure 7 - FIFO Write Cycle
Valid Data
D[7...0]
WR
TXE# T7
T12
T11
T8
T9 T10
Table 4 - FIFO Write Cycle Timings
Time Description Min Max Unit
T7 WR Active Pulse Width 50 ns
T8 WR to RD Pre-Charge Time 50 ns
T9 Data Setup Time before WR Inactive 20 ns
T10 Data Hold Time from WR Inactive 0 ns
T11 WR Inactive to TXE# 5 25 ns
T12 TXE Inactive After WR Cycle 80 ns
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 12
5. Package Parameters
The FT245R is supplied in two different packages. The FT245RL is the SSOP-28 option and the FT245RQ is the
QFN-32 package option. The solder reflow profile for both packages is described in Section 5.3.
5.1 SSOP-28 Package Dimensions
12° Typ
0° - 8°
0.25
0.75 +/-0.20
0.09
2.00 Max
1.75
+/- 0.10
0.05 Min
1.25 +/-0.12
FT245RL
YYXX-A
1
14 15
28
FTDI
5.30 +/-0.30
7.80 +/-0.40
10.20 +/-0.30
1.02 Typ.
0.30 +/-0.012
0.65 +/-0.026
Figure 8 - SSOP-28 Package Dimensions
The FT245RL is supplied in a RoHS compliant 28 pin SSOP package. The package is lead ( Pb ) free and uses a
‘green’ compound. The package is fully compliant with European Union directive 2002/95/EC.
This package has a 5.30mm x 10.20mm body ( 7.80mm x 10.20mm including pins ). The pins are on a 0.65 mm pitch.
The above mechanical drawing shows the SSOP-28 package – all dimensions are in millimetres.
The date code format is YYXX where XX = 2 digit week number, YY = 2 digit year number.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 13
5.2 QFN-32 Package Dimensions
Figure 9 - QFN-32 Package Dimensions
The FT245RQ is supplied in a RoHS compliant leadless QFN-32 package. The package is lead ( Pb ) free, and uses
a ‘green’ compound. The package is fully compliant with European Union directive 2002/95/EC.
This package has a compact 5.00mm x 5.00mm body. The solder pads are on a 0.50mm pitch. The above mechanical
drawing shows the QFN-32 package – all dimensions are in millimetres.
The centre pad on the base of the FT245RQ is not internally connected, and can be left unconnected, or connected to
ground (recommended).
The date code format is YYXX where XX = 2 digit week number, YY = 2 digit year number.
Indicates Pin #1
(Laser Marked)
FT245RQ
32 25
24
17
16
9
8
1
YYXX-A
FTDI
5.000
5.000
18
9
1
2
3
4
5
6
7
8
10111213141516
17
19
20
21
22
23
24
25 26 27 28 29 30 31 32
3.200 +/-0.100
3.200 +/-0.100
0.500
0.250
+/-0.050
0.200 Min
0.500
+/-0.050
0.150 Max
Pin #1 ID
0.800
+/-0.050
0.200 0.050
0.900
+/-0.100
TOP
BOTTOM
SIDE
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 14
5.3 QFN-32 Package Typical Pad Layout
Top View
Figure 10 - Typical Pad Layout for QFN-32 Package
5.4 QFN-32 Package Typical Solder Paste Diagram
Top View
Figure 11 - Typical Solder Paste Diagram for QFN-32 Package
1
17
25
0.500
0.30
0.200 Min
0.500
+/-0.050
0.150 Max
0.20
0.100
3.200 +/-0.100
3.200 +/-0.100
2.50
2.50
Optional GND
Connection
Optional GND
Connection
9
0.500
0.30
0.200 Min
0.500
+/-0.050
0.150 Max
0.20
0.100
2.50
2.50
0.20
0.30
0.60
0.40
0.70
0.60
1
17
25
9
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 15
5.5 Solder Reflow Profile
Critical Zone: when
T is in the range
T to T
Temperature, T (Degrees C)
Time, t (seconds)
25
P
T = 25º C to T
tp
T
p
T
L
t
Preheat
S
t
L
Ramp Up
Lp
Ramp
Down
T Max
S
T Min
S
Figure 12 - FT245R Solder Reflow Profile
The recommended values for the solder reflow profile are detailed in Table 5. Values are shown for both a completely
Pb free solder process (i.e. the FT245R is used with Pb free solder), and for a non-Pb free solder process (i.e. the
FT245R is used with non-Pb free solder).
Table 5 - Reflow Profile Parameter Values
Profile Feature Pb Free Solder Process Non-Pb Free Solder Process
Average Ramp Up Rate (Ts to Tp) 3°C / second Max. 3°C / Second Max.
Preheat
- Temperature Min (TS Min.)
- Temperature Max (TS Max.)
- Time (tS Min to tS Max)
150°C
200°C
60 to 120 seconds
100°C
150°C
60 to 120 seconds
Time Maintained Above Critical Temperature TL:
- Temperature (TL)
- Time (tL)
217°C
60 to 150 seconds
183°C
60 to 150 seconds
Peak Temperature (TP) 260°C 240°C
Time within 5°C of actual Peak Temperature (tP) 20 to 40 seconds 20 to 40 seconds
Ramp Down Rate 6°C / second Max. 6°C / second Max.
Time for T= 25°C to Peak Temperature, Tp8 minutes Max. 6 minutes Max.
The FT245R is supplied in Pb free 28 LD SSOP and QFN-32 packages. The recommended solder reflow profile for
both package options is shown in Figure 12.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 16
6. Device Characteristics and Ratings
6.1 Absolute Maximum Ratings
The absolute maximum ratings for the FT245R devices are as follows. These are in accordance with the Absolute
Maximum Rating System (IEC 60134). Exceeding these may cause permanent damage to the device.
Table 6 - Absolute Maximum Ratings
Parameter Value Unit
Storage Temperature -65°C to 150°C Degrees C
Floor Life (Out of Bag) At Factory Ambient
( 30°C / 60% Relative Humidity)
168 Hours
(IPC/JEDEC J-STD-033A MSL
Level 3 Compliant)*
Hours
Ambient Temperature (Power Applied) -40°C to 85°C Degrees C.
Vcc Supply Voltage -0.5 to +6.00 V
D.C. Input Voltage - USBDP and USBDM -0.5 to +3.8 V
D.C. Input Voltage - High Impedance Bidirectionals -0.5 to +(Vcc +0.5) V
D.C. Input Voltage - All other Inputs -0.5 to +(Vcc +0.5) V
D.C. Output Current - Outputs 24 mA
DC Output Current - Low Impedance Bidirectionals 24 mA
Power Dissipation (Vcc = 5.25V) 500 mW
* If devices are stored out of the packaging beyond this time limit the devices should be baked before use. The
devices should be ramped up to a temperature of 125°C and baked for up to 17 hours.
6.2 DC Characteristics
DC Characteristics ( Ambient Temperature = -40oC to +85oC )
Table 7 - Operating Voltage and Current
Parameter Description Min Typ Max Units Conditions
Vcc1 VCC Operating Supply Voltage 3.3 - 5.25 V
Vcc2 VCCIO Operating Supply Voltage 1.8 - 5.25 V
Icc1 Operating Supply Current - 15 - mA Normal Operation
Icc2 Operating Supply Current 50 70 100 μAUSB Suspend
Table 8 - FIFO Interface and Control Bus Pin Characteristics (VCCIO = 5.0V, Standard Drive Level)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 3.2 4.1 4.9 V I source = 2mA
Vol Output Voltage Low 0.3 0.4 0.6 V I sink = 2mA
Vin Input Switching Threshold 1.3 1.6 1.9 V **
VHys Input Switching Hysteresis 50 55 60 mV **
Table 9 - FIFO Interface and Control Bus Pin Characteristics (VCCIO = 3.3V, Standard Drive Level)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 2.2 2.7 3.2 V I source = 1mA
Vol Output Voltage Low 0.3 0.4 0.5 V I sink = 2mA
Vin Input Switching Threshold 1.0 1.2 1.5 V **
VHys Input Switching Hysteresis 20 25 30 mV **
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 17
Table 10 - FIFO Interface and Control Bus Pin Characteristics (VCCIO = 2.8V, Standard Drive Level)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 2.1 2.6 3.1 V I source = 1mA
Vol Output Voltage Low 0.3 0.4 0.5 V I sink = 2 mA
Vin Input Switching Threshold 1.0 1.2 1.5 V **
VHys Input Switching Hysteresis 20 25 30 mV **
Table 11 - FIFO Interface and Control Bus Pin Characteristics (VCCIO = 5.0V, High Drive Level)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 3.2 4.1 4.9 V I source = 6mA
Vol Output Voltage Low 0.3 0.4 0.6 V I sink = 6mA
Vin Input Switching Threshold 1.3 1.6 1.9 V **
VHys Input Switching Hysteresis 50 55 60 mV **
Table 12 - FIFO Interface and Control Bus Pin Characteristics (VCCIO = 3.3V, High Drive Level)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 2.2 2.8 3.2 V I source = 3mA
Vol Output Voltage Low 0.3 0.4 0.6 V I sink = 8mA
Vin Input Switching Threshold 1.0 1.2 1.5 V **
VHys Input Switching Hysteresis 20 25 30 mV **
Table 13 - FIFO Interface and Control Bus Pin Characteristics (VCCIO = 2.8V, High Drive Level)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 2.1 2.8 3.2 V I source = 3mA
Vol Output Voltage Low 0.3 0.4 0.6 V I sink = 8mA
Vin Input Switching Threshold 1.0 1.2 1.5 V **
VHys Input Switching Hysteresis 20 25 30 mV **
**Inputs have an internal 200kΩ pull-up resistor to VCCIO.
Table 14 - RESET#, TEST Pin Characteristics
Parameter Description Min Typ Max Units Conditions
Vin Input Switching Threshold 1.3 1.6 1.9 V
VHys Input Switching Hysteresis 50 55 60 mV
Table 15 - USB I/O Pin (USBDP, USBDM) Characteristics
Parameter Description Min Typ Max Units Conditions
UVoh I/O Pins Static Output ( High) 2.8 3.6 V RI = 1.5kΩ to 3V3OUT ( D+ )
RI = 15kΩ to GND ( D- )
UVol I/O Pins Static Output ( Low ) 0 0.3 V RI = 1.5kΩ to 3V3OUT ( D+ )
RI = 15kΩ to GND ( D- )
UVse Single Ended Rx Threshold 0.8 2.0 V
UCom Differential Common Mode 0.8 2.5 V
UVDif Differential Input Sensitivity 0.2 V
UDrvZ Driver Output Impedance 26 29 44 Ohms ***
***Driver Output Impedance includes the internal USB series resistors on USBDP and USBDM pins.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 18
6.3 EEPROM Reliability Characteristics
The internal 1024 Bit EEPROM has the following reliability characteristics-
Table 16 - EEPROM Characteristics
Parameter Description Value Unit
Data Retention 15 Years
Read / Write Cycles 100,000 Cycles
6.4 Internal Clock Characteristics
The internal Clock Oscillator has the following characteristics.
Table 17 - Internal Clock Characteristics
Parameter Value Unit
Min Typical Max
Frequency of Operation 11.98 12.00 12.02 MHz***
Clock Period 83.19 83.33 83.47 ns
Duty Cycle 45 50 55 %
***Equivalent to +/-1667ppm.
Table 18 - OSCI, OSCO Pin Characteristics (Optional - Only applies if external Oscillator is used****)
Parameter Description Min Typ Max Units Conditions
Voh Output Voltage High 2.8 - 3.6 V Fosc = 12MHz
Vol Output Voltage Low 0.1 - 1.0 V Fosc = 12MHz
Vin Input Switching Threshold 1.8 2.5 3.2 V
****When supplied the device is configured to use its internal clock oscillator. Users who wish to use an external
oscillator or crystal should contact FTDI technical support.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 19
7. Device Configurations
Please note that pin numbers on the FT245R chip in this section have deliberately been left out as they vary between
the FT245RL and FT245RQ versions of the device. All of these configurations apply to both package options for the
FT245R device. Please refer to Section 4 for the package option pin-out and signal descriptions.
7.1 Bus Powered Configuration
Figure 13 - Bus Powered Configuration
Figure 13 illustrates the FT245R in a typical USB bus powered design configuration. A USB Bus Powered device gets
its power from the USB bus. Basic rules for USB Bus power devices are as follows –
i) On plug-in to USB, the device must draw no more than 100mA.
ii) On USB Suspend the device must draw no more than 500μA.
iii) A Bus Powered High Power USB Device (one that draws more than 100mA) should use the PWREN# pin to keep
the current below 100mA on plug-in and 500μA on USB suspend.
iv) A device that consumes more than 100mA can not be plugged into a USB Bus Powered Hub
v) No device can draw more that 500mA from the USB Bus.
The power descriptor in the internal EEPROM should be programmed to match the current draw of the device.
A Ferrite Bead is connected in series with USB power to prevent noise from the device and associated circuitry (EMI)
being radiated down the USB cable to the Host. The value of the Ferrite Bead depends on the total current required by
the circuit – a suitable range of Ferrite Beads is available from Steward (www.steward.com) for example Steward Part
# MI0805K400R-00.
FT245R
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
100nF
3V3OUT
VCCIO
NC
RESET#
NC
+
100nF
10nF
Vcc
D0
D1
D2
D3
D4
D5
D6
D7
RXF#
WR#
RD#
TXE#
USBDP
USBDM
VCC
1
2
3
4
5
OSCI
OSCO
PWREN#
Ferrite
Bead
+
4.7uF
SHIELD
GND
GND
GND
GND
Vcc
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 20
7.2 Self Powered Configuration
Figure 14 Self Powered Configuration
Figure 14 illustrates the FT245R in a typical USB self powered configuration. A USB Self Powered device gets its
power from its own power supply and does not draw current from the USB bus. The basic rules for USB Self power
devices are as follows –
i) A Self Powered device should not force current down the USB bus when the USB Host or Hub Controller is
powered down.
ii) A Self Powered Device can use as much current as it likes during normal operation and USB suspend as it has its
own power supply.
iii) A Self Powered Device can be used with any USB Host and both Bus and Self Powered USB Hubs
The power descriptor in the internal EEPROM should be programmed to a value of zero (self powered).
In order to meet requirement (i) the USB Bus Power is used to control the RESET# Pin of the FT245R device. When
the USB Host or Hub is powered up the internal 1.5kΩ resistor on USBDP is pulled up to 3.3V, thus identifying the
device as a full speed device to USB. When the USB Host or Hub power is off, RESET# will go low and the device will
be held in reset. As RESET# is low, the internal 1.5kΩ resistor will not be pulled up to 3.3V, so no current will be forced
down USBDP via the 1.5kΩ pull-up resistor when the host or hub is powered down. Failure to do this may cause some
USB host or hub controllers to power up erratically.
Figure 10 illustrates a self powered design which has a 3.3V - 5V supply. A design which is interfacing to 2.8V - 1.8V
logic would have a 2.8V - 1.8V supply to VCCIO, and a 3.3V - 5V supply to VCC
Note : When the FT245R is in reset, the FIFO interface and control pins all go tri-state. These pins have internal
200kΩ pull-up resistors to VCCIO, so they will gently pull high unless driven by some external logic.
FT245R
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
100nF
3V3OUT
VCCIO
NC
RESET#
NC
+
100nF
VCC
D0
D1
D2
D3
D4
D5
D6
D7
RXF#
WR#
RD#
TXE#
USBDP
USBDM
VCC
1
2
3
4
5
OSCI
OSCO
PWREN#
4.7uF
SHIELD
GND GND
GND
GND
VCC = 3.3V - 5V
GND
10k
4k7
100nF
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 21
7.3 USB Bus Powered with Power Switching Configuration
Figure 15 - Bus Powered with Power Switching Configuration
USB Bus powered circuits need to be able to power down in USB suspend mode in order to meet the <= 500μA
total USB suspend current requirement (including external logic). Some external logic can power itself down into a
low current state by monitoring the PWREN# signal. For external logic that cannot power itself down in this way, the
FT245R provides a simple but effective way of turning off power to external circuitry during USB suspend.
Figure 15 shows how to use a discrete P-Channel Logic Level MOSFET to control the power to external logic circuits.
A suitable device would be an International Rectifier (www.irf.com) IRLML6402, or equivalent. It is recommended that
a “soft start” circuit consisting of a 1kΩ series resistor and a 0.1μF capacitor are used to limit the current surge when
the MOSFET turns on. Without the soft start circuit there is a danger that the transient power surge of the MOSFET
turning on will reset the FT245R, or the USB host / hub controller. The values used here allow attached circuitry to
power up with a slew rate of ~12.5V per millisecond, in other words the output voltage will transition from GND to 5V in
approximately 400 microseconds.
Alternatively, a dedicated power switch I.C. with inbuilt “soft-start” can be used instead of a MOSFET. A suitable power
switch I.C. for such an application would be a Micrel (www.micrel.com) MIC2025-2BM or equivalent.
Please note the following points in connection with power controlled designs –
i) The logic to be controlled must have its own reset circuitry so that it will automatically reset itself when power is re-
applied on coming out of suspend.
ii) Set the Pull-down on Suspend option in the internal EEPROM.
iii) The PWREN# pin should be used to switch the power to the external circuitry.
iv) For USB high-power bus powered device (one that consumes greater than 100mA, and up to 500mA of current
from the USB bus), the power consumption of the device should be set in the max power field in the internal
EEPROM. A high-power bus powered device must use this descriptor in the internal EEPROM to inform the
system of its power requirements.
v) For 3.3V power controlled circuits the VCCIO pin must not be powered down with the external circuitry (the
PWREN# signal gets its VCC supply from VCCIO). Either connect the power switch between the output of the
3.3V regulator and the external 3.3V logic or power VCCIO from the 3V3OUT pin of the FT245R.
FT245R
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
100nF
3V3OUT
VCCIO
NC
RESET#
NC
+
100nF
10nF
5V VCC
D0
D1
D2
D3
D4
D5
D6
D7
TXE#
WR#
RD#
RXF#
USBDP
USBDM
VCC
1
2
3
4
5
OSCI
OSCO
PWREN#
Ferrite
Bead
+
4.7uF
SHIELD
GND
GND
GND
GND
0.1uF
0.1uF
1k
Soft Start
Circuit
d
g
sSwitched 5V Power
to External Logic
5V VCC
P-Channel Power
MOSFET
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 22
7.4 USB Bus Powered with 3.3V / 5V Supply and Logic Drive / IO Supply Voltage
Figure 16 - Bus Powered with 3.3V / 5V Supply and Logic Drive
Figure 16 shows a configuration where a jumper switch is used to allow the FT245R to be interfaced with a 3.3V or
5V logic devices. The VCCIO pin is either supplied with 5V from the USB bus, or with 3.3V from the 3V3OUT pin. The
supply to VCCIO is also used to supply external logic.
Please note the following in relation to bus powered designs of this type -
i) The PWREN# signal should be used to power down external logic during USB suspend mode, in order to comply
with the limit of 500μA. If this is not possible, use the configuration shown in Section 7.3.
ii) The maximum current source from USB Bus during normal operation should not exceed 100mA, otherwise a bus
powered design with power switching (Section 7.3) should be used.
Another possible configuration would be to use a discrete low dropout regulator which is supplied by the 5V on the
USB bus to supply 2.8V - 1.8V to the VCCIO pin and to the external logic. VCC would be supplied with the 5V from
the USB bus. With VCCIO connected to the output of the low dropout regulator, would in turn will cause the FT245R
I/O pins to drive out at 2.8V - 1.8V logic levels.
For USB bus powered circuits some considerations have to be taken into account when selecting the regulator –
iii) The regulator must be capable of sustaining its output voltage with an input voltage of 4.35V. A Low Drop Out
(L.D.O.) regulator must be selected.
iv) The quiescent current of the regulator must be low in order to meet the USB suspend total current requirement of
<= 500μA during USB suspend.
An example of a regulator family that meets these requirements is the MicroChip / Telcom TC55 Series of devices
(www.microchip.com). These devices can supply up to 250mA current and have a quiescent current of under 1μA.
FT245R
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
100nF
3V3OUT
VCCIO
NC
RESET#
NC
10nF
D0
D1
D2
D3
D4
D5
D6
D7
TXE#
WR#
RD#
RXF#
USBDP
USBDM
VCC
1
2
3
4
5
OSCI
OSCO
PWREN#
Ferrite
Bead
+
SHIELD
GND
GND
GND
3.3V or 5V Supply
to External Logic
100nF
+
100nF
Vcc
4.7uF
GND
1
Jumper
2
3
Vcc
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 23
8. Example Interface Configurations
8.1 USB to MCU FIFO Interface Example
Figure 17 -Example USB to MCU FIFO Interface
Figure 17 illustrates a typical interfacing between the FT245R and a Microcontroller (MCU) FIFO interface. This
example uses two I/O ports: one port (8 bits) to transfer data, and the other port (4 or 5 bits) to monitor the TXE# and
RXF# status bits and generate the RD# and WR strobes to the FT245R, as required. Using PWREN# for this function
is optional.
If the Remote Wakeup option is enabled in the internal EEPROM, during USB suspend mode RXF# becomes an input
which can be used to wake up the USB host controller by strobing the pin low.
FT245R
A
G
N
D
G
N
D
G
N
D
G
N
D
T
E
S
T
100nF
3V3OUT
VCCIO
NC
RESET#
NC
+
100nF 4.7uF
Vcc
D0
D1
D2
D3
D4
D5
D6
D7
RXF#
WR#
RD#
TXE#
USBDP
USBDM
VCC
1
2
3
4
5
OSCI
OSCO
PWREN#
Microcontroller
I/O10
I/O11
I/O12
I/O13
Ferrite
Bead
GND
GND
GND
+
GND
10nF
Vcc
Vcc
I/O14
I/O15
I/O16
I/O17
I/O20
I/O21
I/O22
I/O23
I/O24
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 24
10. Internal EEPROM Configuration
Following a power-on reset or a USB reset the FT245R will scan its internal EEPROM and read the USB configuration
descriptors stored there. The default values programmed into the internal EEPROM in a brand new device are defined
in Table 19.
Table 19 - Default Internal EEPROM Configuration
Parameter Value Notes
USB Vendor ID (VID) 0403h FTDI default VID (hex)
USB Product ID (PID) 6001h FTDI default PID (hex)
Serial Number Enabled? Yes
Serial Number See Note A unique serial number is generated and programmed into the EEPROM
during device final test.
Pull Down I/O Pins in USB Suspend Disabled Enabling this option will make the device pull down on the FIFO interface
lines when the power is shut off (PWREN# is high)
Manufacturer Name FTDI
Manufacturer ID FT Serial number prefix
Product Description FT245R USB FIFO
Max Bus Power Current 90mA
Power Source Bus Powered
Device Type FT245R
USB Version 0200 Returns USB 2.0 device descriptor to the host. Note: The device is be
a USB 2.0 Full Speed device (12Mb/s) as opposed to a USB 2.0 High
Speed device (480Mb/s).
Remote Wake up Enabled Taking RXF# low will wake up the USB host controller from suspend.
High Current I/Os Disabled Enables the high drive level on the FIFO data bus and control I/O pins
Load VCP Driver Enabled Makes the device load the VCP driver interface for the device.
The internal EEPROM in the FT245R can be programmed over USB using the utility program MPROG. MPROG can
be downloaded from the FTDI website. Version 2.8a or later is required for the FT245R chip. Users who do not have
their own USB Vendor ID but who would like to use a unique Product ID in their design can apply to FTDI for a free
block of unique PIDs. Contact FTDI support for this service.
FT245R USB UART I.C. Datasheet Version 1.05 © Future Technology Devices International Ltd. 2005
Page 25
Disclaimer
Copyright © Future Technology Devices International Limited , 2005.
Version 0.90 - Initial Datasheet Created August 2005
Version 0.94 - Revised Pre-release datasheet October 2005
Version 1.00 - Full datasheet released December 2005
Version 1.02 - Minor revisions to datasheet released 7th December 2005
Version 1.03 - Manufacturer ID added to default EEPROM data January 2006
Version 1.04 - 9th January 2006 Buffer sizes added.
Version 1.05 - 30th January 2006 QFN-32 Package pad layout and solder paste diagrams added.
Neither the whole nor any part of the information contained in, or the product described in this manual, may be
adapted or reproduced in any material or electronic form without the prior written consent of the copyright holder.
This product and its documentation are supplied on an as-is basis and no warranty as to their suitability for any
particular purpose is either made or implied.
Future Technology Devices International Ltd. will not accept any claim for damages howsoever arising as a result of
use or failure of this product. Your statutory rights are not affected.
This product or any variant of it is not intended for use in any medical appliance, device or system in which the failure
of the product might reasonably be expected to result in personal injury.
This document provides preliminary information that may be subject to change without notice.
Contact FTDI
Head Office -
Future Technology Devices International Ltd.
373 Scotland Street,
Glasgow G5 8QB,
United Kingdom
Tel. : +(44) 141 429 2777
Fax. : +(44) 141 429 2758
E-Mail (Sales) : sales1@ftdichip.com
E-Mail (Support) : support1@ftdichip.com
E-Mail (General Enquiries) : admin1@ftdichip.com
Regional Sales Offices -
Future Technology Devices International Ltd.
(Taiwan)
4F, No 16-1,
Sec. 6 Mincyuan East Road,
Neihu District,
Taipei 114,
Taiwan, R.o.C.
Tel.: +886 2 8791 3570
Fax: +886 2 8791 3576
E-Mail (Sales): tw.sales@ftdichip.com
E-Mail (Support): tw.support@ftdichip.com
E-Mail (General Enquiries): tw.admin@ftdichip.com
Future Technology Devices International Ltd.
(USA)
5285 NE Elam Young
Parkway, Suite B800
Hillsboro,
OR 97124-6499
USA
Tel.: +1 (503) 547-0988
Fax: +1 (503) 547-0987
E-Mail (Sales): us.sales@ftdichip.com
E-Mail (Support): us.support@ftdichip.com
E-Mail (General Enquiries): us.admin@ftdichip.com
Website URL : http://www.ftdichip.com