PCA9540BD,118

The PCA9540B is a 1-of-2 bidirectional translating multiplexer, controlled via the I2C-bus. The SCL/SDA upstream pair fans out to two SCx/SDx downstream pairs, or channels. Only one SCx/SDx channel is selected at a time, determined by the contents of the programmable control register.

A power-on reset function puts the registers in their default state and initializes the I2C-bus state machine with no channels selected. The pass gates of the multiplexer are constructed such that the VDD pin can be used to limit the maximum high voltage that is passed by the PCA9540B. This allows the use of different bus voltages on each SCx/SDx pair, so that 1.8 V, 2.5 V or 3.3 V parts can communicate with 5 V parts without any additional protection. External pull-up resistors can pull the bus up to the desired voltage level for this channel. All I/O pins are 5 V tolerant.

Key features include a 1-of-2 bidirectional translating multiplexer, I2C-bus interface logic compatible with SMBus standards, and channel selection via I2C-bus. It supports hot insertion, has low standby current, and operates with a power supply voltage range of 2.3 V to 5.5 V. The device supports a clock frequency of 0 Hz to 400 kHz.

This component is available in an 8-SOIC package and is designed for surface mount applications. ESD protection exceeds 2000 V HBM and 1000 V CDM, with latch-up testing exceeding 100 mA.