Texas Instruments PCA9548APWRG4

Overview

PCA9548APWRG4 from Texas Instruments is an 8-channel bidirectional I²C bus switch with voltage-level translation, active-low reset, and hardware address selection (A0–A2). It operates from 2.3 V to 5.5 V, supports up to 400 kHz clock frequency, and enables resolution of I²C slave address conflicts in multi-sensor server and telecom systems.

For engineers reviewing the PCA9548APWRG4 datasheet, PCA9548APWRG4 pinout, PCA9548APWRG4 application, or PCA9548APWRG4 equivalent, key selection criteria include channel count, reset functionality, I²C timing compliance (Standard/Fast Mode), voltage translation capability across 1.8 V/2.5 V/3.3 V/5 V domains, and thermal performance in TSSOP-24 packaging.

Technical Context

The PCA9548APWRG4 implements eight independent bidirectional pass-gate switches controlled via a single 8-bit I²C register, where each bit enables one SCn/SDn channel. Its internal state machine resets on power-up or RESET assertion, deselecting all channels and initializing I²C communication logic.

Switch operation supports voltage translation by isolating upstream SCL/SDA from downstream SCn/SDn pairs-each pair uses independent external pull-ups to its target bus voltage (e.g., 3.3 V master ↔ 5 V sensor), while all I/O pins remain 5-V tolerant and R_ON stays ≤10 Ω at 5 V.

Key Specifications

Pinout & Package

Packaged in TSSOP-24 (PW) with body size 7.80 mm × 4.40 mm, the PCA9548APWRG4 features 24 leads with exposed thermal pad (RGE variant differs; this part uses PW).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I²C switch applications.

Compared with PCA9548APWRG4, TCA9548APWR offers superior ESD immunity and lower quiescent current for next-gen deployments, while PCA9544APW provides a direct footprint-compatible downgrade for reduced channel requirements - both retain identical I²C register mapping and reset behavior.

Availability

PCA9548APWRG4 is available at Aetrix Electronics and suitable for server rack management, telecom router backplanes, and factory automation PLCs requiring stable component supply and long-term industrial availability.

Supply support for PCA9548APWRG4 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company specializing in analog and embedded processing technologies, with leadership in interface, power management, and signal chain solutions.

The PCA9548A product line was designed to resolve I²C slave address collisions in dense multi-peripheral systems, targeting servers, networking equipment, and industrial controllers where bus isolation and voltage translation are critical.

FAQ

What is the maximum I²C clock frequency supported by the PCA9548APWRG4?

The PCA9548APWRG4 supports I²C clock frequencies up to 400 kHz, meeting Fast-Mode timing specifications including t_SCL (1.3 μs min), t_SCH (0.6 μs min), and t_BUF (1.3 μs min). This allows full-speed communication with modern microcontrollers and sensors without clock stretching. The PCA9548APWRG4 maintains signal integrity across all eight channels under these conditions when bus capacitance remains ≤400 pF.

How does the PCA9548APWRG4 handle voltage-level translation between different I²C buses?

The PCA9548APWRG4 enables voltage-level translation by using separate external pull-up resistors on each SCn/SDn channel - pulled to their respective bus voltages (e.g., 3.3 V for master, 5 V for sensor). Its pass-gate architecture and 5-V-tolerant I/Os ensure signal integrity across 1.8 V, 2.5 V, 3.3 V, and 5 V domains. The PCA9548APWRG4 itself is powered by VCC, which defines the maximum voltage passed through the switches.

Can the PCA9548APWRG4 recover from a stuck I²C bus condition?

Yes - the PCA9548APWRG4 features an active-low RESET input that forces a full internal reset of the I²C state machine and deselects all channels when asserted for ≥6 ns. This recovers communication if any downstream bus locks low, without requiring a power cycle. The PCA9548APWRG4 also performs automatic power-on reset (POR) at VCC rise, ensuring known initial state on startup.

What package type is used for the PCA9548APWRG4, and what are its key mechanical dimensions?

The PCA9548APWRG4 uses the TSSOP-24 (PW) package with nominal body dimensions of 7.80 mm × 4.40 mm and standard 0.65 mm lead pitch. It includes 24 gull-wing leads and no thermal pad. This package is RoHS-compliant, surface-mountable, and optimized for automated assembly in high-volume industrial PCBs - distinct from the VQFN (RGE) or SOIC variants of the same device family.

How many PCA9548APWRG4 devices can share the same I²C bus, and how is addressing managed?

Up to eight PCA9548APWRG4 devices can coexist on a single I²C bus using the three hardware address pins A0, A1, and A2. Each pin is strapped to VCC or GND to configure a unique 3-bit address, yielding slave addresses from 0x70 to 0x77. The PCA9548APWRG4 responds only to its assigned address, enabling scalable expansion of I²C switching capacity without software arbitration overhead.