CA9542 is a low-voltage, 2-channel bidirectional I²C/SMBus multiplexer with interrupt capability and level translation support. It enables a single I²C/SMBus master to connect to one of two downstream I²C channels, effectively expanding the bus while preventing conflicts between slave devices. Designed for demanding server and telecom environments, the device ensures robust signal isolation and reliable multi-device communication.

The multiplexer features one upstream SCL/SDA pair and two downstream channel pairs (SCL0/SDA0 and SCL1/SDA1). Channel selection is performed through an internal control register, allowing only one active downstream channel at a time. The Power-On Reset function restores the I²C bus state machine and deselects channels, helping recover from bus lock-up situations.

Each downstream channel includes its own active-low interrupt input (INT0, INT1), while the device outputs a combined interrupt signal (INT) to the upstream master. The CA9542 supports mixed-voltage operation between 1.8 V, 2.5 V, 3.3 V, and 5.0 V devices by using external pull-up resistors. It operates at up to 1 MHz Fast Mode Plus, supports hot insertion, integrates noise filters on I²C lines, and offers compatibility with up to eight I²C addresses.

Compact, versatile and robust, the CA9542 is an excellent choice for systems requiring channel isolation, multi-device management, or voltage-level flexibility within an I²C/SMBus topology.