1 Features
. I2C to Parallel port expander
. Operating power-supply voltage range of 1.65 V to
5.5 V
. Allows bidirectional voltage-level translation and
gpio expansion between 1.8-V, 2.5-V, 3.3-V, and
5-V I2C bus and P-ports
. Low standby current consumption of 1 μA
. 5-V Tolerant I/O ports
. 400-kHz Fast I2C bus
. Hardware address pin allows two TCA6408A
Devices on the same I2C/SMBus bus
. Active-low reset ( RESET) input
. Open-drain active-low interrupt ( INT) output
. Input and output configuration register
. Polarity inversion register
. Internal power-on reset
. Power up with all channels configured as inputs
. No glitch on power up
. Noise filter on SCL and SDA inputs
. Latched outputs with high-current drive maximum
capability for directly driving LEDs
. Latch-up performance exceeds 100 mA Per JESD
78, class II
. Schmitt-trigger action allows slow input transition
and better switching noise immunity at the SCL
and SDA inputs
. ESD Protection exceeds JESD 22
. 2000-V Human body model (A114-A)
. 1000-V Charged-device model (C101)

2 Applications
. Servers
. Routers (telecom switching equipment)
. Personal computers
. Personal electronics (gaming consoles)
. Industrial automation
. Products with GPIO-limited processors

3 Description
The TCA6408A is a 16-pin device that provides 8-
bits of general purpose parallel input/output (I/O)
expansion for the two-line bidirectional I2C bus (or
SMBus) protocol. This device can operate with a
power supply voltage ranging from 1.65 V to 5.5 V
on both the I2C bus side (VCCI) and on the P-port side
(VCCP). This allows the TCA6408A to interface with
next-generation microprocessors and microcontrollers
on the SDA/SCL side, where supply levels are
dropping down to conserve power. In contrast to
the dropping power supplies of microprocessors and
microcontrollers, some PCB components such as
LEDs remain at a 5-V power supply.
The device supports both 100-kHz (Standard-mode)
and 400-kHz (Fast-mode) clock frequencies. I/O
expanders such as the TCA6408A provide a simple
solution when additional I/Os are needed for switches,
sensors, push-buttons, LEDs, fans, and so forth.