Texas Instruments TCA9543ADR

Overview

TCA9543ADR from Texas Instruments is a low-voltage, 2-channel bidirectional I²C bus switch with interrupt logic and active-low reset. It enables I²C master-to-slave routing across two isolated downstream channels (SC0/SD0 and SC1/SD1), supports voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses, operates from 1.65 V to 5.5 V, and handles up to 400-kHz clock frequency - ideal for resolving I²C slave address conflicts in multi-sensor systems.

For engineers reviewing the TCA9543ADR datasheet, TCA9543ADR pinout, TCA9543ADR application, or TCA9543ADR equivalent, key selection considerations include its dual-channel programmable switching via I²C control register, active-low interrupt aggregation (INT = INT0 ∧ INT1), power-on and hardware reset recovery, 5.5-V tolerant inputs, and low R_ON (≤10 Ω at 4.5–5.5 V) enabling minimal signal degradation in high-density I²C topologies.

Technical Context

The TCA9543ADR implements a dual-channel, bidirectional translating switch architecture controlled by an 8-bit I²C-accessible register where bits B0 and B1 select channel 0, channel 1, both, or none. Its interrupt logic performs a wired-AND of INT0 and INT1 onto the single active-low INT output, enabling centralized fault detection without polling.

Each channel features independent voltage-domain isolation enabled by external pull-up resistors tied to distinct V_DPU rails (V_DPUM, V_DPU0, V_DPU1), allowing mixed-voltage communication - e.g., a 3.3-V master communicating with 1.8-V temperature sensors on channel 0 and 5-V EEPROMs on channel 1 - while maintaining I²C timing compliance per Standard- and Fast-mode specifications.

Key Specifications

Pinout & Package

TCA9543ADR is packaged in a 14-pin TSSOP (PW) with nominal body size 5.00 mm × 4.40 mm, optimized for space-constrained PCB layouts while maintaining thermal performance (R_θJA = 130.9°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9544A and PCA9542A, the TCA9543ADR uniquely balances dual-channel flexibility, integrated interrupt management, and hardware reset - making it optimal for systems requiring robust, self-recovering I²C segmentation without over-engineering.

Availability

TCA9543ADR is available at Aetrix Electronics and suitable for server thermal management, telecom switching equipment, and factory automation I/O modules requiring stable component supply, long-term manufacturability, and guaranteed traceable sourcing.

Supply support for TCA9543ADR 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 interface solutions and industrial-grade signal integrity.

The TCA9543ADR belongs to TI's I²C bus switch product line, designed specifically to resolve slave address conflicts and enable mixed-voltage I²C system architectures in servers, networking gear, and industrial control systems.

FAQ

What is the function of the RESET pin on the TCA9543ADR?

The RESET pin on the TCA9543ADR is an active-low input that forces the internal I²C state machine into reset and deselects both downstream channels. When asserted for ≥4 ns, it clears any bus-lock condition - such as a stuck-low SDA on a downstream channel - and restores the device to its default configuration. The TCA9543ADR must be pulled up externally to V_CC; leaving RESET floating may cause unpredictable behavior.

How does the TCA9543ADR handle voltage-level translation between different I²C buses?

The TCA9543ADR enables voltage-level translation by allowing independent pull-up resistors on each I²C segment: upstream (SDA/SCL) to V_DPUM, channel 0 (SD0/SC0) to V_DPU0, and channel 1 (SD1/SC1) to V_DPU1. Its pass-gate architecture uses V_CC to clamp maximum output voltage, permitting interoperability between 1.8-V, 2.5-V, 3.3-V, and 5-V devices without external level shifters - as confirmed in TI's SCPS206B datasheet Section 8.1.

Can the TCA9543ADR be used with more than two I²C slave devices simultaneously?

Yes - the TCA9543ADR supports multiple slaves per channel. Each downstream channel (SC0/SD0 and SC1/SD1) can connect to multiple I²C slaves, provided total bus capacitance remains ≤400 pF per segment. The device itself does not limit slave count per channel; instead, it isolates traffic so that addressing conflicts on one channel do not affect the other. This is explicitly validated in the "Description" and "Applications" sections of the TCA9543ADR datasheet.

What is the role of the A0 and A1 pins on the TCA9543ADR?

The A0 and A1 pins on the TCA9543ADR are hardware-configurable address inputs that set the device's 7-bit I²C slave address. They allow up to four TCA9543ADR units to coexist on the same I²C bus with addresses 0x70–0x73. Both pins must be hard-wired to either V_CC or GND - no internal pull-ups exist - and their states are sampled at power-on reset. This addressing scheme is defined in Section 8.6.1 ("Device Address") of the official TI datasheet.

Does the TCA9543ADR support Fast-mode Plus (1 MHz) I²C operation?

No - the TCA9543ADR is rated for Standard-mode (100 kHz) and Fast-mode (400 kHz) I²C operation only, as specified in Section 6.6 ("I²C Interface Timing Requirements") of the datasheet. Its propagation delay (≤1 ns at 15-pF load) and switching characteristics are characterized up to 400 kHz; operation beyond this frequency is not guaranteed and may violate setup/hold timing margins. For 1-MHz systems, TI recommends alternatives like the TCA9548A.