Texas Instruments PCA9543APWRG4

Overview

PCA9543APWRG4 from Texas Instruments is a 2-channel bidirectional I²C bus switch with interrupt logic and active-low reset, designed to resolve I²C slave address conflicts in multi-sensor systems. It supports voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses, features dual active-low interrupt inputs (INT0/INT1), one active-low interrupt output (INT), and operates across 2.3 V to 5.5 V supply range at up to 400 kHz clock frequency.

For engineers reviewing the PCA9543APWRG4 datasheet, PCA9543APWRG4 pinout, PCA9543APWRG4 application, or PCA9543APWRG4 equivalent, this device is selected for I²C bus isolation, hot-insertion-capable sensor multiplexing, interrupt aggregation in server management controllers, and mixed-voltage I²C subsystems requiring channel-selectable routing without glitch on power-up.

Technical Context

The PCA9543APWRG4 implements two independent bidirectional pass-gate switches controlled via an 8-bit I²C-accessible control register. Channel selection (B0/B1 bits) enables either SC0/SD0, SC1/SD1, both, or none - with deselection enforced after power-on reset or RESET assertion. Its interrupt logic performs AND of INT0 and INT1 to drive open-drain INT output, while preserving interrupt status in bits 4–5 of the control register for master interrogation.

Each channel supports independent voltage translation via external pull-up resistors referenced to VDPU0 or VDPU1, decoupled from master-side VDPUM. The device uses no internal pull-ups on A0/A1 address pins and incorporates 5.5-V-tolerant I/O, latch-up immunity (>100 mA per JESD78), and ESD protection (2000-V HBM, 1000-V CDM).

Key Specifications

Pinout & Package

TSSOP-14 package (5.00 mm × 4.40 mm), thermally optimized for surface-mount assembly in space-constrained industrial and telecom PCBs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9544APWR and PCA9546APWR, the PCA9543APWRG4 delivers optimal balance of compact dual-channel routing, hardware interrupt consolidation, and ultra-low standby current - making it the preferred choice for space- and power-constrained I²C multiplexing where precise fault attribution is critical.

Availability

PCA9543APWRG4 is available at Aetrix Electronics and suitable for server baseboard management, industrial sensor hubs, and telecom router monitoring requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for PCA9543APWRG4 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 leader specializing in analog, embedded processing, and connectivity technologies, with decades of expertise in I²C infrastructure and system-level power management.

The PCA9543APWRG4 belongs to TI's I²C switch and multiplexer product line, engineered specifically for robust bus isolation, mixed-voltage interoperability, and interrupt-aware sensor subsystems in mission-critical infrastructure.

FAQ

What is the I²C slave address range supported by the PCA9543APWRG4?

The PCA9543APWRG4 supports four fixed I²C slave addresses: 0x70, 0x71, 0x72, and 0x73. These are determined by the logic states of the A0 and A1 pins (e.g., A1=0, A0=0 → 0x70). All addresses are 7-bit, with R/W bit appended during transmission. No software-configurable addressing is implemented - configuration is strictly hardware-pin based per the PCA9543APWRG4 datasheet.

Does the PCA9543APWRG4 support hot insertion of downstream I²C slaves?

Yes, the PCA9543APWRG4 explicitly supports hot insertion per its datasheet. Its architecture ensures that unpowered or disconnected slaves on SCn/SDn channels do not load or disrupt the master-side SDA/SCL lines. This behavior is enabled by the device's high-impedance OFF-state and absence of internal pull-ups - allowing safe connection/disconnection of peripherals while the PCA9543APWRG4 and master remain powered.

How does the PCA9543APWRG4 handle simultaneous interrupts on INT0 and INT1?

The PCA9543APWRG4 drives the INT output low whenever either INT0 or INT1 is asserted - effectively performing a wired-AND function. Both interrupt flags (bits 4 and 5) are latched in the control register and remain set until cleared by host read. Thus, the PCA9543APWRG4 preserves visibility of concurrent interrupts on both channels, enabling the host to identify and service multiple fault sources in sequence.

Can the PCA9543APWRG4 translate between 1.8-V and 5-V I²C buses without external components?

No - the PCA9543APWRG4 enables voltage translation but requires external pull-up resistors on each I²C segment: VDPUM for master-side SDA/SCL, VDPU0 for Channel 0 (SD0/SC0), and VDPU1 for Channel 1 (SD1/SC1). The device itself does not generate or regulate these voltages; it only passes logic levels through its low-R_ON switches, limiting maximum output voltage to VCC. Therefore, correct pull-up placement and voltage selection are mandatory for reliable 1.8-V ↔ 5-V operation in the PCA9543APWRG4.

What happens to the PCA9543APWRG4 channels during power-up or RESET assertion?

Upon power-up or when RESET is pulled low, the PCA9543APWRG4 forces both channels to deselect - clearing bits B0 and B1 in the control register and disabling all SCn/SDn paths. This default state prevents bus contention and ensures the master initiates communication only after explicit software configuration. The internal power-on reset (POR) triggers at VPOR ≈ 1.6–2.1 V (depending on VCC), and RESET deassertion restores normal operation with all channels inactive.