General description
The PCA9541A 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
PCA9541A/01 powers up with Channel 0 selected
PCA9541A/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 Ronswitches
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