4-channel 1.65- to 5.5-V I2C/SMBus multiplexer with interrupt & voltage translation

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.