The PCA9546A is a quad bidirectional translating switch that is operated by the I2C bus. The SCL/SDA upstream pair spreads out to four downstream pairs, or channels. Individual SCn/SDn channels or combinations of channels can be selected based on the contents of the programmable control register. An active-low reset (RESET) input enables the PCA9546A to recover from a situation in which one of the downstream I2C buses becomes trapped in a low state. Pulling RESET low resets the I2C state machine and deselects all channels, as does the internal power-on reset operation. The switches’ pass gates are designed so that the VCC pin can be utilized to limit the maximum high voltage passed by the PCA9546A. This enables the use of multiple bus voltages on each pair, allowing 1.8-V, 2.5-V, or 3.3-V parts to communicate with 5-V parts without requiring additional safety. External pull-up resistors bring the bus voltage up to the necessary level for each channel. All I/O pins are 5.5-volt tolerant.
Datasheet