Texas Instruments PCA9548ADBR

Overview

PCA9548ADBR 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 systems. Used in server backplanes and telecom switching equipment for channel-isolated sensor communication.

For engineers reviewing the PCA9548ADBR datasheet, PCA9548ADBR pinout, PCA9548ADBR application, or PCA9548ADBR equivalent, this page delivers verified electrical specs, package mapping to SSOP-24, confirmed I²C timing compliance (Standard/Fast Mode), real-world voltage translation capability across 1.8 V/2.5 V/3.3 V/5 V domains, and validated alternative part selection guidance.

Technical Context

The PCA9548ADBR 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 active-low RESET assertion, deselecting all channels and initializing I²C logic.

Switch architecture uses low-R_ON MOSFETs (4–45 Ω depending on V_CC) enabling voltage translation without level shifters; V_CC sets maximum high-voltage pass-through, while external pull-ups define per-channel bus voltage. All I/O pins are 5-V tolerant, and ESD protection meets ±2000-V HBM, ±1000-V CDM.

Key Specifications

Pinout & Package

PCA9548ADBR is packaged in a 24-pin SSOP (DB) with body size 8.20 mm × 5.30 mm. Pinout conforms to TI's DB package variant (top view), with dedicated SDA/SCL upstream bus, eight SCn/SDn downstream pairs, three address inputs (A0–A2), active-low RESET, VCC, and GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9548A and PCA9544A, PCA9548ADBR uniquely combines full 8-channel capacity, hardware RESET, and proven 5-V tolerance - making it the only option supporting fault-resilient, high-density I²C expansion in mission-critical infrastructure.

Availability

PCA9548ADBR is available at Aetrix Electronics and suitable for server backplanes, telecom switching equipment, and factory automation systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for PCA9548ADBR 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 in high-density embedded systems - enabling scalable sensor networks, modular telecom hardware, and reliable server management interfaces.

FAQ

What is the function of the RESET pin on the PCA9548ADBR?

The RESET pin on the PCA9548ADBR is an active-low asynchronous input that forces immediate deselection of all eight channels and resets the internal I²C state machine. When asserted for ≥6 ns, it recovers the device from stuck-bus conditions on any downstream SCn/SDn pair without requiring power cycling. The PCA9548ADBR must be pulled up to VCC externally; leaving it floating may cause unpredictable behavior.

Does the PCA9548ADBR support voltage translation between different I²C bus voltages?

Yes, the PCA9548ADBR supports bidirectional voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V I²C buses. Its pass-gate architecture uses VCC as the upper voltage limit, while external pull-up resistors on each SCn/SDn pair set the local bus voltage. All I/O pins are 5-V tolerant, allowing safe interfacing between mixed-voltage peripherals without additional level-shifting components.

How many PCA9548ADBR devices can share the same I²C bus?

Up to eight PCA9548ADBR devices can operate on the same I²C bus using hardware address configuration via A0, A1, and A2 pins. Each pin accepts VCC or GND, yielding 2³ = 8 unique 7-bit slave addresses (0x70–0x77). This enables hierarchical I²C expansion - for example, one PCA9548ADBR per blade in an 8-slot chassis, each managing its own set of sensors.

What is the maximum I²C clock frequency supported by the PCA9548ADBR?

The PCA9548ADBR supports I²C clock frequencies up to 400 kHz, meeting Fast-Mode timing requirements per JEDEC standards. It also fully complies with Standard-Mode (100 kHz) operation. Propagation delay is ≤1 ns (CL = 50 pF), ensuring timing margins are preserved even at maximum speed. Bus capacitance must remain ≤400 pF per segment for reliable 400-kHz operation.

Is the PCA9548ADBR compatible with SMBus protocols?

Yes, the PCA9548ADBR is explicitly designed to be I²C and SMBus compatible. It adheres to SMBus 2.0 timing and electrical specifications, including timeout detection, alert response, and packet error checking support. Its active-low RESET input and power-on reset behavior align with SMBus system management requirements, making it suitable for use in SMBus-based platform management controllers (PMCs) and baseboard management controllers (BMCs).