PCA9545APWR (Marking: PD545A) — PCA9545 TSSOP20 I2C Switch / Multiplexer IC Why choose this component Solve I2C address conflicts and expand a single I2C master onto multiple downstream buses without redesigning endpoint devices. Simplifies system wiring and troubleshooting by isolating groups of I2C devices onto separate channels. Small TSSOP20 package provides a compact, boardfriendly footprint for spaceconstrained designs. Key benefits Centralized bus management: Select and isolate up to four downstream I2C channels from a single upstream master, enabling multiple identicaladdress devices on the same system. Clean system integration: Makes it easy to segment devices for noise isolation, power sequencing, or separate bus voltages. Minimal board area: TSSOP20 package allows placement close to connectors or sensors while preserving PCB space. Core attributes Model: PCA9545APWR Marking: PD545A Package: TSSOP20, surfacemount IC Functionality: I2C switch / multiplexer for managing multiple downstream I2C channels from a single master Compatibility: Designed for use with standard I2C devices and masters; ideal for microcontroller and embedded systems that use the I2C protocol Construction: Integrated silicon IC in a TSSOP20 plastic package for reliable boardmounted operation Performance: Provides reliable channel selection and bus isolation to simplify communication with multiple peripherals Typical applications and use cases Sensor arrays with identical addresses: Connect multiple identical temperature, humidity, or light sensors to the same host without address conflicts by switching between channels. Modular peripheral expansion: Segment I2C peripherals (e.g., EEPROMs, ADCs, power management ICs) onto separate channels to reduce crosstalk and make firmware control straightforward. Development and testing fixtures: Route different device sets to a single test master for production or bench testing, allowing selective access without rewiring. Design and integration tips Place the PCA9545A close to the connector or sensor cluster it manages to minimize trace length and reduce noise coupling. Use the device to gate groups of peripherals during power sequencing or firmwaredriven resets to improve system robustness. Check your master's I2C control method to ensure straightforward channel selection and integration into your firmware flow. What's in the package PCA9545APWR IC, marking PD545A, in TSSOP20 package ready for PCB assembly. This PCA9545APWR (PD545A) TSSOP20 IC is a practical, compact solution for engineers who need to expand or organize I2C buses without changing peripheral hardware, making it useful for embedded systems, sensor networks, and production test fixtures.