The PCA9548A device contains eight bidirectional translating switches that can be operated via the I2C bus. The SCL/SDA upstream pair spreads out to eight downstream pairs, or channels. Individual SCx/SDx channels or combinations of channels can be selected based on the contents of the programmable control register. These downstream routes can help to resolve I2C slave address problems. For example, if the application requires eight identical digital temperature sensors, one sensor can be linked to each channel (07). The system master can reset the PCA9548A in the event of a timeout or other incorrect operation by asserting a low in the RESET input. Similarly, the power-on reset disables all channels and restarts the I2C/SMBus state machine. Asserting RESET causes the same reset and initialization to take place without turning off the part. This provides for recovery in case one of the downstream I2C buses becomes stuck in a low condition. The switches’ pass gates are designed so that the VCC pin can be utilized to limit the maximum high voltage passed by the PCA9548A. 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-volt tolerant.
Datasheet