NXP Semiconductors PCA9542APW,112

Overview

PCA9542APW,112 from NXP Semiconductors is a 1-of-2 bidirectional I²C-bus translating multiplexer with integrated interrupt logic, operating from 2.3 V to 5.5 V supply, supporting up to 400 kHz clock frequency, and enabling voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V buses in embedded system interconnects.

For engineers reviewing the PCA9542APW,112 datasheet, PCA9542APW,112 pinout, PCA9542APW,112 application, or PCA9542APW,112 equivalent, this device serves as a channel-selectable bus isolation and level-shifting solution for multi-voltage I²C subsystems requiring interrupt aggregation, hot-insertion support, and low standby current (≤1 µA).

Technical Context

The PCA9542APW,112 implements a dual-channel pass-gate architecture controlled via an 8-bit I²C-accessible control register, where bits B2–B0 determine active channel selection (000 = none, 100 = channel 0, 101 = channel 1). Its interrupt logic performs AND-combining of two active-low inputs (INT0, INT1) into a single open-drain output (INT), with status bits readable in real time.

Voltage translation is achieved by leveraging VDD as the clamp reference for pass-gate threshold control, allowing independent bus voltage domains on SC0/SD0 and SC1/SD1 while maintaining 5 V tolerance on all I/O pins. The power-on reset initializes registers to zero and deselects all channels without glitch.

Key Specifications

Pinout & Package

TSSOP14 package (SOT402-1): plastic thin shrink small outline, 14-lead, body width 4.4 mm, lead pitch 0.65 mm, moisture sensitivity level (MSL) 1 - suitable for high-density PCB layouts and reflow-soldered production.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9542APW,112, the PCA9544APW,112 offers scalable channel count with identical voltage translation and interrupt features, while the TCA9544APWR trades interrupt functionality for alternate vendor sourcing - neither provides pin-compatible replacement without design review.

Availability

PCA9542APW,112 is available at Aetrix Electronics and suitable for server management subsystems, industrial PLC I/O expansion, and automotive body control modules requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for PCA9542APW,112 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The PCA9542A product line delivers I²C-bus multiplexing and interrupt aggregation for multi-peripheral embedded systems, designed to simplify bus topology management and reduce host-side software complexity in resource-constrained environments.

FAQ

What is the primary function of the PCA9542APW,112 in an I²C system?

The PCA9542APW,112 functions as a 1-of-2 bidirectional I²C-bus multiplexer that routes upstream SCL/SDA signals to either of two downstream SCx/SDx channel pairs. It also integrates interrupt logic that combines INT0 and INT1 into a single active-low INT output. This enables selective bus access and centralized fault reporting without modifying I²C protocol behavior - a core capability of the PCA9542APW,112.

Does the PCA9542APW,112 support voltage translation between different I²C bus voltages?

Yes, the PCA9542APW,112 supports voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V I²C buses by using its VDD supply as a clamp reference for pass-gate threshold control. External pull-up resistors set each channel's bus voltage level independently. All I/O pins are 5 V tolerant, and the PCA9542APW,112 maintains signal integrity across domains without external level shifters.

How does the interrupt logic of the PCA9542APW,112 operate?

The PCA9542APW,112 provides two active-low interrupt inputs (INT0, INT1), one per downstream channel, and a single active-low open-drain interrupt output (INT) that acts as their logical AND. Status bits INT0 and INT1 are readable in the control register, allowing the host to identify which channel triggered the event. This interrupt aggregation reduces GPIO usage and simplifies firmware - a defining feature of the PCA9542APW,112.

What is the recommended power-up sequence for reliable operation of the PCA9542APW,112?

The PCA9542APW,112 incorporates an internal power-on reset (POR) that holds the device in reset until VDD reaches VPOR (1.6 V to 2.1 V). Upon release, registers initialize to zero and all channels remain deselected - ensuring no bus contention. To guarantee proper initialization, VDD must ramp monotonically and exceed VPOR; no external reset circuitry is required. This POR behavior is intrinsic to the PCA9542APW,112 design.

Can the PCA9542APW,112 be used in hot-swap applications?

Yes, the PCA9542APW,112 supports hot insertion: its pass-gate architecture and power-on reset ensure no glitches occur during live connection/disconnection of downstream I²C devices. The device remains transparent to upstream timing when idle, and channel selection only affects active paths. This makes the PCA9542APW,112 suitable for field-serviceable systems like modular servers or diagnostic equipment where peripherals may be added or removed without powering down.