Document No.: FT_000329
FT232BL/BQ USB UART IC Datasheet Version 2.2
Clearance No.: FTDI# 171
3.3 LQFP and QFN Package Pin Out Description
Pin No.
Name
USBDP
USBDM
Type
I/O
Description
USB Data Signal Plus ( Requires 1.5k pull-up to 3V3OUT or RSTOUT# )
USB Data Signal Minus
7
8
I/O
Table 3.1 USB Interface Group
Pin No.
Name
VCCIO
GND
Type
PWR
Description
+3.0 volt to +5.25 volt VCC to the UART interface pins 10...12, 14...16 and
18...25. When interfacing with 3.3V external logic in a bus powered design connect
VCCIO to a 3.3V supply generated from the USB bus. When interfacing with 3.3V
external logic in a self powered design connect VCCIO to the 3.3V supply of the
external logic. Otherwise connect to VCC to drive out at 5V CMOS level.
13
9,17
6
PWR
Device ground supply pins
3.3 volt Output from the integrated LDO regulator This pin should be decoupled to
GND using a 33nF ceramic capacitor in close proximity to the device pin. Its prime
purpose is to provide the internal 3.3V supply to the USB transceiver cell and the
RSTOUT# pin. A small amount of current (<= 5mA) can be drawn from this pin to
power external 3.3v logic if required.
3V3OUT
Output
3,26
30
VCC
AVCC
AGND
PWR
PWR
PWR
+4.35 volt to +5.25 volt VCC to the device core, LDO and non-UART interface pins
Device analogue power supply for internal x8 clock multiplier
29
Device analogue ground supply for internal x8 clock multiplier
Table 3.2 Power and Ground Group
Pin No.
Name
Type
Description
Active low reset pin. This can be used by an external device to reset the FT232B.
If not required can be left unconnected, or pulled up to VCC.
4
RESET#
Input
Output of the internal Reset Generator. Stays high impedance for ~ 5ms after
VCC > 3.5V and the internal clock starts up, and then clamps its output to the
3.3v output of the internal regulator. Taking RESET# low will also force RSTOUT#
to drive low. RSTOUT# is NOT affected by a USB Bus Reset
5
RSTOUT#
Output
12
11
TXLED#
RXLED#
O.C
O.C
LED Drive – Pulses Low when Transmitting Data via USB
LED Drive – Pulses Low when Receiving Data via USB
Input to 6MHz Crystal Oscillator Cell. This pin can also be driven by an external
6MHz clock if required. Note: Switching threshold of this pin is VCC/2, so if driving
from an external source, the source must be driving at 5V CMOS level or AC-
coupled to centre around VCC/2.
27
XTIN
Input
Output from 6MHz Crystal Oscillator Cell. XTOUT stops oscillating during USB
suspend, so take care if using this signal to clock external logic.
28
31
XTOUT
TEST
Output
Input
Puts the device into IC test mode. Must be tied to GND for normal operation,
otherwise the device will appear to fail.
Table 3.3 Miscellaneous Signal Group
Copyright © 2011 Future Technology Devices International Limited
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