NXP Semiconductors PCA9543CPW,118

Overview

PCA9543CPW,118 from NXP Semiconductors is a 2-channel bidirectional I²C-bus switch with 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 selective routing of SDA/SCL signals to downstream channels SC0/SD0 or SC1/SD1 in server management, sensor hub, and multi-peripheral embedded systems.

For engineers reviewing the PCA9543CPW,118 datasheet, PCA9543CPW,118 pinout, PCA9543CPW,118 application, or PCA9543CPW,118 equivalent, key selection criteria include its dual-channel interrupt handling (INT0/INT1 → open-drain INT), hardware address configuration via A0/A1 pins, low Ron (~9 Ω typical at 5 V), and TSSOP14 package compatibility with high-density PCB layouts.

Technical Context

The PCA9543CPW,118 implements a register-controlled analog switch architecture with independent channel enable bits (B0/B1) and read-only interrupt status bits (INT0/INT1) in its 8-bit control register. Its pass-gate design uses VDD as a voltage clamp reference, enabling level translation without external components.

Interrupt logic performs AND-combining of INT0 and INT1 into a single open-drain INT output, while internal power-on reset and active-low RESET pin ensure deterministic bus recovery from stuck-bus faults. Channel selection takes effect only after STOP condition, preventing glitches during switching.

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, RoHS-compliant, suitable for reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9543CPW,118, the PCA9544APW,118 offers scalable channel count without changing PCB layout, while the TCA9544APWR provides alternate sourcing with minor timing and voltage-clamp variations requiring validation in mixed-voltage designs.

Availability

PCA9543CPW,118 is available at Aetrix Electronics and suitable for server management, industrial sensor hubs, automotive body control modules, and medical diagnostic equipment requiring stable component supply and long-term lifecycle support.

Supply support for PCA9543CPW,118 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 broad portfolio coverage in interface, power management, and microcontroller technologies.

The PCA9543 series belongs to NXP's I²C-bus switch and multiplexer product line, designed specifically to resolve address collisions, isolate fault domains, and enable voltage translation in resource-constrained embedded systems.

FAQ

What is the I²C slave address of PCA9543CPW,118?

The PCA9543CPW,118 uses a fixed 7-bit slave address of 0x70 (1110000b), determined by its "C" variant designation. Address bits A1 and A0 are hardwired internally, so external pull-up/down resistors on those pins have no effect. This address allows up to four PCA9543CPW,118 devices on the same bus when combined with PCA9543APW,118 (0x72) and PCA9543BPW,118 (0x74) for a total of 12 unique addresses across the family.

How does the RESET pin function on PCA9543CPW,118?

The RESET pin on PCA9543CPW,118 is an active-low asynchronous input that forces the internal I²C state machine into reset and deselects all channels immediately. A minimum pulse width of 4 ns (tw(rst)L) is required. The pin must be pulled up to VDD externally; leaving it floating may cause erratic channel behavior. RESET operates independently of VDD ramp rate and recovers the device from stuck-bus conditions without requiring a full power cycle.

Can PCA9543CPW,118 translate between 5 V and 1.8 V I²C buses?

Yes, PCA9543CPW,118 supports voltage translation between 5 V and 1.8 V I²C buses using its VDD-referenced pass-gate architecture. When VDD = 1.8 V, Vo(sw) is clamped to ≤1.5 V (typ), safely limiting downstream voltage. External pull-up resistors on each SCx/SDx pair must match their respective bus voltage. The device's 5 V-tolerant inputs allow direct connection to 5 V masters even when VDD = 1.8 V.

What is the maximum capacitive load supported on each channel of PCA9543CPW,118?

PCA9543CPW,118 supports up to 400 pF total capacitance per bus line (Cb), as specified in the dynamic characteristics table. This aligns with standard I²C-bus specifications for fast-mode operation (400 kHz). Exceeding this limit risks violating tR/tF timing requirements and may cause communication failures. For systems approaching this limit, consider reducing pull-up resistance or adding series termination to maintain signal integrity.

How does interrupt handling work when both INT0 and INT1 are asserted simultaneously on PCA9543CPW,118?

When both INT0 and INT1 are asserted LOW simultaneously, the PCA9543CPW,118 drives INT LOW (AND logic), and bits 4 and 5 of the control register are both set to '1' upon read. The host must read the control register, interpret both interrupt flags, then sequentially enable each channel to poll downstream devices. The PCA9543CPW,118 does not prioritize interrupts; resolution order is determined entirely by firmware sequencing.