PCA9545APW

Specialized Overview

The PCA9545APW is a quad bidirectional translating switch manufactured by Texas Instruments, designed for I2C and SMBus systems. It fans out one upstream SCL/SDA pair to four downstream SCn/SDn channel pairs. The device allows any individual channel or combination of channels to be selected via a programmable control register. It operates within a supply voltage range of 2.3 V to 5.5 V and supports mixed-mode signal operation. Key electrical parameters include a maximum power dissipation of 400 mW, a bandwidth of 0.4 MHz, and an operating temperature range from -40 °C to +85 °C. The component is housed in a 20-pin TSSOP package.

Specialized Feature Summary

• Provides four independent bidirectional translating switches for I2C and SMBus bus expansion
• Allows flexible configuration where any single channel or multiple channels can be simultaneously enabled
• Supports mixed-mode signal operation between different voltage domains on the bus

Specialized Applications

• Expanding I2C bus capacity in embedded systems with multiple slave devices
• Isolating specific I2C peripherals to prevent bus contention or lockups
• Enabling communication with multiple sensors or modules sharing the same address space

Specialized Procurement Notes

Verify the manufacturer marking matches Texas Instruments specifications. Confirm the package type is TSSOP-20 and the suffix indicates the correct tape and reel or cut tape quantity if applicable. Ensure the part number aligns with the required voltage and temperature ratings for the target application environment.

Specialized Selection Notes

Select this component when independent control over multiple downstream I2C buses is required. Unlike the PCA9544A which selects only one channel at a time, the PCA9545A permits simultaneous activation of multiple channels. Verify that the system voltage levels are compatible with the 2.3 V to 5.5 V operating range and that the 20-pin TSSOP footprint fits the PCB layout constraints.

Specialized Part Context

The PCA9545A belongs to the broader family of Texas Instruments PCA95xx interface devices, which includes repeaters, switches, and expanders. This specific model functions as a multiplexer rather than a simple buffer like the PCA9515A. It is distinct from the TCA9545 series, which may offer additional features such as interrupt outputs or reset functionality not present in the standard PCA9545A variant.

Specialized Replacement Considerations

The PCA9545AD serves as a pin-compatible alternative in SOIC-20 packaging. For designs requiring interrupt capabilities, the TCA9545A series offers enhanced features while maintaining functional compatibility.