General description
The PCA9541 is a 2-to-1 I2C-bus master selector designed for high reliability dual master I2C-bus applications where system operation is required, even when one master fails or the controller card is removed for maintenance. The two masters (for example, primary and back-up) are located on separate I2C-buses that connect to the same downstream I2C-bus slave devices. I2C-bus commands are sent by either I2C-bus master and are used to select one master at a time. Either master at any time can gain control of the slave devices if the other master is disabled or removed from the system. The failed master is isolated from the system and will not affect communication between the on-line master and the slave devices on the downstream I2C-bus.

Features
■ 2-to-1 bidirectional master selector
■ I2C-bus interface logic; compatible with SMBus standards
■ PCA9541/01 powers up with Channel 0 selected
■ PCA9541/03 powers up with no channel selected and either master can take control of the bus
■ Active LOW interrupt input
■ 2 active LOW interrupt outputs
■ Active LOW reset input
■ 4 address pins allowing up to 16 devices on the I2C-bus
■ Channel selection via I2C-bus
■ Bus initialization/recovery function
■ Bus traffic sensor
■ 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
■ Software identical for both masters
■ Low standby current
■ Operating power supply voltage range of 2.3 V to 5.5 V
■ 6.0 V tolerant inputs
■ 0 Hz to 400 kHz clock frequency
■ ESD protection exceeds 2000 V HBM per JESD22-A114, 200 V MM per JESD22-A115, and 1000 V CDM per JESD22-C101
■ Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
■ Packages offered: SO16, TSSOP16, HVQFN16

Applications
■ High reliability systems with dual masters
■ Gatekeeper multiplexer on long single bus
■ Bus initialization/recovery for slave devices without hardware reset
■ Allows masters without arbitration logic to share resources