UMFT230XA Datasheet
Version 1.4
Document Reference No.: FT_000519 Clearance No.: FTDI#269
5.6 Variable IO Voltage Supply
Vcc = 1.8V – 3.3V
TXD
RXD
TXD
RTS#
CTS#
RXD
RTS#
CTS#
MCU
VCCIO
VCC
3V3OUT
VBUS
GND
Solder Link JP1 - Open
Solder Link JP2 - Closed
Viewing pins thourgh the board
from the top.
Figure 5.4 – USB Bus Powered 3.3V Logic Drive
The FT230X can process signals at CMOS/TTL logic levels in the range of 1.8V to 3.3V. This section
describes how to utilise this feature.
Figure 5.4 shows a configuration where the FT230X is interfaced to a device with IOs operating in the
range of 1.8V – 3.3V. The IO ports of this module need to be powered with a voltage level that is equal
to the level of the signals it is processing. Since the FT230X’s embedded voltage regulator only outputs
3V3 the IO ports will need to be powered from another power source when operating at voltage levels
other than 3.3V. (Note that Figure 5.4 is for illustration only and that the pins do not actually go all the
way through the PCB)
By default, a short is present between 3V3OUT (embedded voltage regulator) and VCCIO (IO port’s
power input) by solder links JP1. If an external power supply is used to power the IO ports this solder
links needs to be open. This can be done by removing the solder linking the two pads of the solder links.
The configuration described in this section can be implemented in either bus-powered mode or self-
powered mode.
Note 1: The CBUS and DBUS pins are 5V tolerant; however these signals cannot drive signals at 5V
TTL/CMOS. VCCIO is not 5V tolerant; applying 5V to VCCIO will damage the chip.
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