Texas Instruments PCA9548ADWR

Overview

PCA9548ADWR from Texas Instruments is an 8-channel bidirectional I²C bus switch with voltage-level translation, active-low reset, and hardware address configuration (A0–A2). It operates from 2.3 V to 5.5 V, supports up to 400 kHz clock frequency, features <10 Ω typical R_ON, and enables resolution of I²C slave address conflicts in multi-sensor server and industrial control systems.

For engineers reviewing the PCA9548ADWR datasheet, PCA9548ADWR pinout, PCA9548ADWR application, or PCA9548ADWR equivalent, this page delivers verified electrical specs, channel-select timing behavior, reset recovery characteristics, package-specific terminal mapping, and real-world use cases for I²C bus expansion and level-shifting designs.

Technical Context

The PCA9548ADWR 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.

It supports Standard-Mode (100 kHz) and Fast-Mode (400 kHz) I²C timing, provides 5-V-tolerant inputs, and uses VCC-referenced pass gates to enable voltage translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses-without external level shifters-by assigning dedicated pull-up resistors per channel.

Key Specifications

Pinout & Package

PCA9548ADWR is supplied in a 24-pin SOIC (DW) package measuring 15.40 mm × 7.50 mm, with standard 0.600-inch body width and 1.27 mm lead pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9548ADWR, TCA9548APWR offers superior thermal and ESD performance for harsh environments, while PCA9544ADWR reduces channel count and footprint for simpler systems-neither is pin-compatible without layout revision, but both share identical I²C register mapping and reset behavior.

Availability

PCA9548ADWR is available at Aetrix Electronics and suitable for server rack management, industrial sensor hubs, and telecom line card designs requiring stable component supply, long-term manufacturability, and guaranteed traceability.

Supply support for PCA9548ADWR 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 headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The PCA9548A product line was designed specifically to resolve I²C slave address conflicts and enable voltage-level translation in multi-node embedded systems-targeting server, networking, and factory automation applications where bus scalability and interoperability are critical.

FAQ

What is the maximum I²C clock frequency supported by the PCA9548ADWR?

The PCA9548ADWR supports I²C clock frequencies up to 400 kHz, fully compliant with Fast-Mode specifications. This allows high-speed polling of multiple downstream devices without compromising timing margins. The device maintains signal integrity across all eight channels at this rate when bus capacitance remains ≤400 pF and pull-up resistors are sized per TI's Rp(max) vs Cb curves. PCA9548ADWR does not support Fast-Mode Plus (1 MHz) or High-Speed Mode.

How does the PCA9548ADWR handle voltage-level translation between different I²C buses?

The PCA9548ADWR enables voltage-level translation by using VCC as the reference for its pass-gate threshold, allowing independent pull-up resistors on each SCn/SDn channel to set local bus voltage (1.8 V, 2.5 V, 3.3 V, or 5 V). Signals pass bidirectionally with minimal distortion because the switch architecture does not buffer or regenerate logic levels. PCA9548ADWR itself must be powered at the highest voltage present on any connected bus, and all I/O pins are 5-V tolerant regardless of VCC setting.

Can the PCA9548ADWR recover from a stuck I²C bus condition without power cycling?

Yes. The PCA9548ADWR includes an active-low RESET input that, when asserted for ≥6 ns, clears the internal control register, deselects all eight channels, and reinitializes the I²C state machine-restoring normal operation without interrupting VCC. This feature is essential for recovering from downstream bus lockups (e.g., a slave holding SDA low). PCA9548ADWR also performs automatic power-on reset when VCC rises above VPOR (~1.5 V), ensuring safe startup even after brownout events.

What are the hardware address options for the PCA9548ADWR on the I²C bus?

The PCA9548ADWR uses three address pins-A0, A1, and A2-to configure its 7-bit I²C slave address. Each pin can be tied to VCC or GND, yielding eight possible addresses: 0x70 through 0x77. This allows up to eight PCA9548ADWR devices to coexist on the same I²C bus without address conflict. All address pins must remain static during I²C transactions; changing them mid-communication will cause address mismatch and failed ACKs. PCA9548ADWR does not support software-configurable addresses.

Is the PCA9548ADWR compatible with SMBus protocols?

Yes. The PCA9548ADWR is explicitly designed to be I²C and SMBus compatible, supporting SMBus Alert Response Address (ARA) and Timeout functionality per SMBus specification v3.0. Its timing parameters-including tBUF, tHD:STA, and tLOW-meet SMBus requirements for both Standard- and Fast-Mode operation. The device tolerates SMBus-specific voltage thresholds (e.g., VIL = 0.3×VCC, VIH = 0.7×VCC) and handles packet error checking (PEC) transparently since it operates at the physical layer without modifying data content. PCA9548ADWR functions identically in SMBus and I²C systems.