NXP Semiconductors PCA9543APW,112

Overview

PCA9543APW,112 from NXP Semiconductors is a 2-channel bidirectional I²C-bus switch with integrated interrupt logic and active-low reset, operating from 2.3 V to 5.5 V supply, supporting up to 400 kHz clock frequency, 5 V-tolerant I/O, and voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V buses. It enables isolated I²C bus expansion in multi-sensor systems and modular server backplanes.

For engineers reviewing the PCA9543APW,112 datasheet, PCA9543APW,112 pinout, PCA9543APW,112 application, or PCA9543APW,112 equivalent, key selection criteria include channel-selectable I²C isolation, dual interrupt input handling (INT0/INT1), active-low reset recovery for stuck-bus conditions, and TSSOP14 package compatibility with high-density PCB layouts.

Technical Context

The PCA9543APW,112 implements two independent pass-gate channels controlled via an 8-bit I²C-accessible control register, where B0/B1 bits select channel 0, channel 1, both, or none - with activation deferred until STOP condition to prevent glitches. Its interrupt logic monitors INT0 and INT1 asynchronously and outputs their AND result on open-drain INT pin, while preserving status in read-accessible register bits.

Reset functionality operates independently of I²C communication: asserting RESET low for ≥4 ns resets the internal state machine and deselects all channels, recovering from downstream bus lockup without host intervention. Voltage translation is achieved through VDD-referenced pass-gate threshold control, enabling level-shifting without external components when VDD is set ≤ lowest downstream bus voltage.

Key Specifications

Pinout & Package

TSSOP14 package (SOT402-1), 4.4 mm body width, 0.65 mm lead pitch, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9544APW,112, the PCA9543APW,112 offers lower cost and reduced standby current for 2-channel use cases, while PCA9543BPW,118 provides seamless address conflict resolution without altering hardware design or firmware I²C addressing logic.

Availability

PCA9543APW,112 is available at Aetrix Electronics and suitable for server management, multi-sensor IoT nodes, and industrial PLC I/O expansion requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for PCA9543APW,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 specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with leadership in I²C, SMBus, and power management ICs.

The PCA9543A/43B product line was designed to solve I²C bus contention and voltage-domain interoperability challenges in modular electronic systems, targeting high-reliability embedded control and sensor aggregation.

FAQ

What is the primary function of the PCA9543APW,112 in an I²C system?

The PCA9543APW,112 functions as a bidirectional 2-channel I²C-bus switch that isolates upstream master communication from two downstream I²C segments. It enables selective routing of SCL/SDA signals, supports voltage translation between 1.8 V–5 V domains, and integrates interrupt aggregation and active-low reset - all critical for reliable bus expansion in dense embedded systems. The PCA9543APW,112 achieves this with minimal latency and no glitch on power-up.

How does the PCA9543APW,112 handle I²C bus lockup conditions?

The PCA9543APW,112 recovers from I²C bus lockup via its active-low RESET pin: asserting RESET low for ≥4 ns resets the internal state machine and deselects all channels, releasing stuck SCL/SDA lines regardless of downstream device state. This hardware-based recovery operates independently of I²C communication and complements the internal power-on reset, which initializes all registers to zero at startup. The PCA9543APW,112 thus ensures deterministic bus recovery without host firmware intervention.

Can the PCA9543APW,112 translate between different I²C voltage levels, and how is it configured?

Yes, the PCA9543APW,112 performs voltage translation by using its VDD supply as a clamp reference: setting VDD ≤ lowest downstream bus voltage (e.g., 3.3 V for 3.3 V/5 V interfacing) limits Vo(sw) to prevent overvoltage on lower-voltage devices. External pull-up resistors on each SCx/SDx pair set final logic levels. All I/O pins are 5 V tolerant, allowing direct connection to 5 V masters. The PCA9543APW,112 requires no external level-shifting components when VDD is correctly configured per application voltage domains.

What is the role of the INT, INT0, and INT1 pins on the PCA9543APW,112?

INT0 and INT1 are active-low interrupt inputs tied to downstream I²C devices on channel 0 and channel 1 respectively; they feed into the PCA9543APW,112's interrupt logic. INT is an active-low open-drain output that asserts when either INT0 or INT1 is low (logical AND). The PCA9543APW,112 also latches INT0/INT1 states into readable control register bits, enabling the master to poll and identify the interrupt source channel before reconfiguring the switch - making the PCA9543APW,112 ideal for interrupt-driven sensor systems.

Is the PCA9543APW,112 pin-compatible with other members of the PCA9543 family?

Yes, the PCA9543APW,112 is pin-compatible with PCA9543AD,112 (SO14) and PCA9543BPW,118 (TSSOP14), sharing identical pin configuration, function mapping, and electrical characteristics. Differences are limited to package type (TSSOP14 vs. SO14) and I²C slave address (PCA9543A vs. PCA9543B variant). This allows direct substitution in TSSOP14 layouts and facilitates address conflict resolution in multi-device systems - all while retaining full functionality of the PCA9543APW,112.