1.

General description

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.

state machine with no channels selected.

limit the maximum high voltage that will be 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.

2.

Features

and 1000 V CDM per JESD22-C101

PCA9540B

Rev. 04 — 3 September 2009

Product data sheet