The TCA9544A is a quad bidirectional translating switch controlled via the I2C bus. The SCL/SDA upstream pair fans out to four downstream pairs, or channels. Any individual SCn/SDn channel or combination of channels can be selected, determined by the contents of the programmable control register. 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.
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