. General description
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.

FEATUREs
■ 1-of-2 bidirectional translating multiplexer
■ I2C-bus interface logic; compatible with SMBus standards
■ Channel selection via I2C-bus
■ Power up with all multiplexer channels deselected
■ Low Ron switches
■ Allows voltage level translation between 1.8 V, 2.5 V, 3.3 V and 5 V buses
■ No glitch on power-up
■ Supports hot insertion
■ Low standby current
■ Operating power supply voltage range of 2.3 V to 5.5 V
■ 5 V tolerant inputs
■ 0 Hz to 400 kHz clock frequency
■ ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per JESD2-A115 and 1000 V CDM per JESD22-C101
■ Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
■ Packages offered: SO8, TSSOP8, XSON8U