NXP Semiconductors PCA9543AD,112

Overview

The PCA9543AD,112 from NXP Semiconductors is a 2-channel bidirectional I²C-bus switch with integrated interrupt logic and active-low reset, designed for bus isolation and voltage translation between 1.8 V, 2.5 V, 3.3 V, and 5 V domains. It features dual SCx/SDx downstream channels, two independent active-low interrupt inputs (INT0, INT1), one active-low open-drain interrupt output (INT), and programmable channel selection via I²C control register. It enables robust multi-voltage I²C system expansion in server management, industrial PLCs, and embedded sensor hubs.

For engineers reviewing the PCA9543AD,112 datasheet, PCA9543AD,112 pinout, PCA9543AD,112 application, or PCA9543AD,112 equivalent, key selection criteria include its SO14 package compatibility, 2.3 V to 5.5 V supply range, 400 kHz Fast-mode I²C support, low Ron (≤30 Ω), and interrupt-aware channel arbitration-critical for fault-tolerant bus architectures requiring hot-swap capability and bus recovery.

Technical Context

The PCA9543AD,112 implements a dual-channel pass-gate architecture controlled by an 8-bit I²C-accessible register where B1/B0 bits select channel 0, channel 1, both, or none. Its interrupt logic latches INT0/INT1 states into bits 4–5 of the control register, enabling master-side interrupt source identification without channel activation. The device uses VDD as a voltage clamp reference to enable level translation across mismatched buses.

Its internal power-on reset (POR) initializes all channels to deselected state at VPOR ≥ 1.6 V, and the external active-low RESET pin provides hardware recovery from stuck-bus conditions with tw(rst)L ≥ 4 ns. All I/O pins are 5 V tolerant, and the switch supports hot insertion with no glitch on power-up.

Key Specifications

Pinout & Package

PCA9543AD,112 is housed in a plastic small outline package (SO14), 14-lead, body width 3.9 mm (SOT108-1), with standard 1.27 mm pitch and surface-mount footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9544APW,118 and TCA9544APWR, the PCA9543AD,112 delivers optimal balance of channel count, Fast-mode speed, address configurability, and SO14 footprint-making it the preferred choice for compact, dual-bus I²C isolation where expandability beyond two channels is unnecessary.

Availability

PCA9543AD,112 is available at Aetrix Electronics and suitable for server baseboard management, industrial PLC I/O expansion, and embedded sensor hub designs requiring stable component supply, guaranteed long-term availability, and traceable sourcing.

Supply support for PCA9543AD,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 leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in interface, power management, and embedded processing technologies.

The PCA9543AD,112 belongs to NXP's PCA954X family of I²C/SMBus multiplexers and switches, engineered specifically for robust bus isolation, voltage translation, and interrupt-aware system management in resource-constrained embedded platforms.

FAQ

What is the primary function of the PCA9543AD,112 in an I²C system?

The PCA9543AD,112 acts 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 mismatched bus voltages (1.8 V to 5 V), and integrates interrupt aggregation and hardware reset-making PCA9543AD,112 essential for scalable, fault-tolerant I²C architectures.

Does the PCA9543AD,112 support Fast-mode I²C operation at 400 kHz?

Yes, the PCA9543AD,112 fully supports Fast-mode I²C operation up to 400 kHz, as confirmed in its dynamic characteristics table. Its propagation delay (tPD ≤ 0.3 ns), rise/fall time specifications, and bus timing compliance ensure reliable operation across Standard- and Fast-mode protocols-critical for high-throughput sensor data acquisition in systems using PCA9543AD,112.

How does the PCA9543AD,112 handle voltage level translation between different I²C domains?

The PCA9543AD,112 uses its VDD supply voltage to limit the maximum pass-through voltage (Vo(sw)) across its pass-gate switches. For example, with VDD = 3.3 V, Vo(sw) is clamped to ≤2.8 V, enabling safe communication between a 5 V master and 3.3 V/2.5 V/1.8 V peripherals-provided external pull-up resistors set each bus to its target voltage. This eliminates external level shifters in PCA9543AD,112-based designs.

Can the PCA9543AD,112 be used with multiple devices on the same I²C bus?

Yes, the PCA9543AD,112 supports up to four devices on one I²C bus via hardware-configurable A0 and A1 pins, yielding four unique slave addresses (E0h–E7h). Additionally, the PCA9543B variant offers alternate addresses (F0h–F7h), allowing up to 12 total PCA9543A/43B devices on a single bus-enabling flexible topology scaling without address conflicts in large PCA9543AD,112 deployments.

What is the role of the RESET pin on the PCA9543AD,112?

The active-low RESET pin on the PCA9543AD,112 forces a hardware reset of the internal I²C state machine and deselects all channels when asserted for ≥4 ns. This recovers the device from bus lockup scenarios-such as a downstream device holding SDA low indefinitely-ensuring deterministic operation. An external pull-up resistor to VDD is mandatory, and RESET is fully compatible with the internal power-on reset (POR) circuitry of PCA9543AD,112.