The NXP PCA9542APW,118 is a 2-channel I²C and SMBus multiplexer that lets one master bus segment talk to two downstream buses with separate addresses. Packaged in a 14-TSSOP (4.40 mm width), it is a surface-mount part for mid-density boards where a smaller footprint than an SOIC matters.
ROHS3 compliant.
What the 2-channel mux means for the I²C bus
Two channels means you can isolate two downstream buses from each other and from the upstream master. This solves the classic I²C address conflict — two devices with the same fixed address sit on separate channels, and the master talks to only one channel at a time. The SMBus compatibility also matters for power-management and battery-monitoring peripherals that use the SMBus protocol's timeout and alert lines.