Document No.: FT_000329
FT232BL/BQ USB UART IC Datasheet Version 2.2
Clearance No.: FTDI# 171
8 UART Interface Configurations
The following sections illustrate possible UART configurations for the FT232B.
8.1 USB RS232 Converter Configuration
Figure 8.1 USB-RS232 Converter Configuration
Figure 7.1 illustrates how to connect the UART interface of the FT232B to a TTL – RS232 Level Converter
I.C. to make a USB RS232 converter using the popular “213” series of TTL to RS232 level converters.
These devices have 4 transmitters and 5 receivers in a 28-pin SSOP package and feature an in-built
voltage converter to convert the 5v (nominal) VCC to the ±9 volts required by RS232. An important
feature of these devices is the SHDN# pin which can power down the device to a low quiescent current
during USB suspend mode.
The device used in the example is a Exar/Sipex SP213EHCA which is capable of RS232 communication at
up to 500K baud. If a lower baud rate is acceptable, then several pin compatible alternatives are
available such as Sipex SP213ECA , Maxim MAX213CAI and Analog Devices ADM213E which are good for
communication at up to 115,200 baud. If a higher baud rate is desired, use a Maxim MAX3245CAI part
which is capable of RS232 communication at rates of up to 1M baud. The MAX3245 is not pin compatible
with the 213 series devices, also its SHDN pin is active high so connect this to PWREN# instead of
SLEEP#.
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