1 Features
1. Low Standby Current Consumption
. I2C to Parallel Port Expander
. Open-Drain Active-Low Interrupt Output
. Active-Low Reset Input
. Operating Power-Supply Voltage Range of 1.65 V
to 5.5 V
. 5-V Tolerant I/O Ports
. 400-kHz Fast I2C Bus
. Two Hardware Address Pins Allow up to Four
Devices on the I2C/SMBus
. Input and Output Configuration Register
. Polarity Inversion Register
. Power-Up With All Channels Configured as Inputs
. No Glitch on Power Up
. Noise Filter on SCL/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
. 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 (example: Gaming Consoles)
• Industrial Automation
• Products With GPIO-Limited Processors

3 Description
The TCA9538 is a 16-pin device that provides 8 bits
of general purpose parallel input and output (I/O)
expansion for the two-line bidirectional I2C bus (or
SMBus) protocol. The device can operate with a
power supply voltage ranging from 1.65 V to 5.5 V.
The device supports both 100-kHz (Standard-mode)
and 400-kHz (Fast-mode) clock frequencies. I/O
expanders such as the TCA9538 provide a simple
solution when additional I/Os are needed for
switches, sensors, push-buttons, LEDs, fans, etc.
The features of the TCA9538 include an interrupt that
is generated on the INT pin whenever an input port
changes state. The A0 and A1 hardware selectable
address pins allow up to four TCA9538 devices on
the same I2C bus. The device can also be reset to its
default sate by using the RESET feature or by cycling
the power supply and causing a power-on reset.