Applications of the PCA9543A will contain an I²C (or SMBus) master device and up to two I²C slave devices. The downstream channels are ideally used to resolve I²C slave address conflicts. For example, if two identical digital temperature sensors are needed in the application, one sensor can be connected at each channel: 0 and 1. When the temperature at a specific location needs to be read, the appropriate channel can be enabled and the other channel switched off, the data can be retrieved, and the I²C master can move on and read the next channel.

In an application where the I²C bus will contain many additional slave devices that do not result in I²C slave address conflicts, these slave devices can be connected to any desired channel to distribute the total bus capacitance across both channels. If both switches will be enabled simultaneously, additional design requirements must be considered (See Design Requirements and Detailed Design Procedure).