1 Features
1• 1-of-4 Bidirectional Translating Switches
• I2C Bus and SMBus Compatible
• Four Active-Low Interrupt Inputs
• Active-Low Interrupt Output
• Three Address Pins, Allowing up to Eight
TCA9544A Devices on the I2C Bus
• Channel Selection Via I2C Bus
• Power-Up With All Switch Channels Deselected
• Low RON Switches
• Allows Voltage-Level Translation Between 1.8-V,
2.5-V, 3.3-V, and 5-V Buses
• No Glitch on Power-Up
• Supports Hot Insertion
• Low Standby Current
• Operating Power Supply Voltage Range of
1.65 V to 5.5 V
• 5.5-V Tolerant Inputs
• 0 to 400-kHz Clock Frequency
• Latch-Up Performance Exceeds 100 mA Per
JESD 78
• ESD Protection Exceeds JESD 22
– 4000-V Human-Body Model (A114-A)
– 1500-V Charged-Device Model (C101)

2 Applications
• Servers
• Routers (Telecom Switching Equipment)
• Factory Automation
• Products With I2C Slave Address Conflicts (For
Example, Multiple, Identical Temp Sensors)

3 Description
The TCA9544A is a 4-channel, bidirectional
translating I2C Muliplexer. The master SCL/SDA
signal pair is directed to one of the four channels of
slave devices, SC0/SD0-SC3/SD3. Four interrupt
inputs (INT3–INT0), one for each of the downstream
pairs, are provided. One interrupt output (INT) acts as
an AND of the four interrupt inputs.
A power-on reset function returns the registers to
their default state and initializes the I2C state
machine, with all channels deselected.
The pass gates of the switches are constructed such
that the VCC pin can be used to limit the maximum
high voltage which will be passed by the TCA9544A.
This allows the use of different bus voltages on each
pair, so that 1.8-V, 2.5-V, or 3.3-V parts can
communicate with 5-V parts without any additional
protection. External pull-up resistors pull the bus up
to the desired voltage level for each channel. All I/O
pins are 5.5 V tolerant.