Texas Instruments

PCA9545APW  

Specialized Backplane Connectors

PCA9545APW Description

The PCA9545APW from Texas Instruments is an I²C/SMBus translating switch designed for bidirectional voltage-level translation between multiple I²C buses. Housed in a 20-pin TSSOP package, this obsolete but robust IC operates within a 2.3V to 5.5V supply range, making it compatible with mixed-voltage systems. It features four bidirectional channels, enabling seamless communication between I²C master and slave devices operating at different logic levels. The device is RoHS3 compliant, REACH unaffected, and rated MSL 1 (Unlimited) for moisture sensitivity, ensuring reliability in industrial environments.

PCA9545APW Features

• Four-channel I²C/SMBus switch with bidirectional voltage translation (2.3V–5.5V).
• Low ON resistance for minimal signal distortion.
• I²C bus arbitration support, preventing contention during multi-master operation.
• Hardware address pins for configuring up to eight unique addresses, reducing conflicts in dense systems.
• Power-on reset ensures default channel selection at startup.
• SMBus-compliant with 100 kHz standard-mode and 400 kHz fast-mode I²C support.
• Surface-mount (TSSOP-20) packaging for compact PCB designs.

PCA9545APW Applications

• Mixed-voltage I²C systems: Bridges 3.3V and 5V logic domains in embedded designs.
• Multi-bus management: Expands I²C connectivity in servers, telecom backplanes, and industrial controllers.
• Sensor hubs: Routes signals between multiple sensors and microcontrollers in IoT/automotive systems.
• Redundant systems: Isolates failed bus segments in mission-critical applications.
• Test equipment: Enables dynamic bus switching for debugging multi-device I²C networks.

Conclusion of PCA9545APW

The PCA9545APW excels in multi-bus I²C systems requiring voltage translation and channel isolation. Its four-channel architecture, hardware configurability, and wide voltage range make it ideal for high-reliability applications, despite its obsolete status. Engineers favor this IC for simplifying complex bus topologies while maintaining signal integrity. For legacy designs or systems needing backward compatibility, the PCA9545APW remains a pragmatic choice.

PCA9545APW Documents

Download datasheets and manufacturer documentation for PCA9545APW

Datasheets :

PCA9545A      

PCN Design/Specification :

Design 22/Feb/2022       Datasheet Update 25/Jun/2014