Texas Instruments PCA9546ADGVR

Overview

PCA9546ADGVR from Texas Instruments is a low-voltage, 4-channel bidirectional I²C/SMBus switch with active-low reset, designed to resolve slave address conflicts and enable voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V buses. It features programmable channel selection via I²C control register, 2.3-V to 5.5-V operating supply, and 400-kHz Fast-Mode support - deployed in server backplanes and telecom switching equipment.

For engineers reviewing the PCA9546ADGVR datasheet, PCA9546ADGVR pinout, PCA9546ADGVR application, or PCA9546ADGVR equivalent, key selection criteria include its 16-pin TSSOP package, 4-channel independent/combined switching capability, 5.5-V tolerant inputs, <9 Ω typical R_ON, and hardware-addressable I²C slave interface (A0–A2).

Technical Context

The PCA9546ADGVR implements four independent bidirectional pass-gate switches controlled by an 8-bit I²C-accessible register, where B0–B3 bits directly enable/disable channels 0–3. Its internal power-on reset (VPOR = 1.6–2.1 V) and external active-low RESET input (t_WL ≥ 6 ns) both force deselection of all channels and clear the I²C state machine.

Switch operation supports voltage translation by isolating upstream (SCL/SDA) and downstream (SCn/SDn) bus domains - each with independent pull-up voltages (V_DPUX) - while maintaining signal integrity via low propagation delay (<1 ns at CL = 50 pF) and 5.5-V-tolerant I/O pins.

Key Specifications

Pinout & Package

PCA9546ADGVR is housed in a 16-pin TSSOP package (5.00 mm × 4.40 mm), lead-free and RoHS-compliant. Pin functions are validated per TI SCPS148G datasheet Rev G (May 2016).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9548APWR and PCA9544ADGVR, PCA9546ADGVR delivers optimal balance of compact 16-pin TSSOP packaging, ultra-low standby current (0.1 μA), and hardware-assisted bus recovery - making it the preferred choice for space-constrained, reliability-critical 4-channel I²C expansion.

Availability

PCA9546ADGVR is available at Aetrix Electronics and suitable for server management, telecom switching equipment, industrial PLC backplanes, and mixed-voltage sensor hubs requiring stable component supply and long-term production continuity.

Supply support for PCA9546ADGVR 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 solutions, with decades of expertise in I²C infrastructure and power-efficient interface ICs.

The PCA9546ADGVR belongs to TI's I²C switch and multiplexer product line, engineered specifically to solve slave address conflicts and enable seamless voltage-domain bridging in high-density computing and communications systems.

FAQ

What is the primary function of the PCA9546ADGVR in an I²C system?

The PCA9546ADGVR functions as a 4-channel bidirectional I²C/SMBus switch that resolves slave address conflicts by isolating downstream devices onto independent channels. It enables selective communication with one or more I²C slaves via software-controlled channel enable bits (B0–B3) in its I²C-accessible control register - without modifying slave firmware or hardware addressing. This makes PCA9546ADGVR essential in systems like servers and telecom gear where multiple identical sensors or peripherals share the same I²C address.

Does the PCA9546ADGVR support voltage-level translation between different I²C bus voltages?

Yes, the PCA9546ADGVR supports voltage-level translation by allowing independent pull-up voltages on each channel (V_DPU0–3) and the upstream bus (V_DPUM). Its pass-gate architecture lets 1.8-V, 2.5-V, or 3.3-V slaves communicate with a 5-V master - provided external pull-ups are set to appropriate voltages and VCC is selected to match the highest desired pass voltage (e.g., VCC = 3.3 V for 3.3-V domain translation). All I/O pins are 5.5-V tolerant, ensuring safe operation across mixed-voltage configurations.

How does the RESET pin on the PCA9546ADGVR improve system reliability?

The active-low RESET pin on the PCA9546ADGVR provides hardware-based recovery from I²C bus lockup - such as when a downstream slave holds SDA low indefinitely. Asserting RESET low for ≥6 ns forces deselection of all channels and resets the internal I²C state machine, restoring bus functionality without requiring a full power cycle. This feature is critical in unattended systems like network switches or industrial controllers, where software-initiated recovery may not be possible during fault conditions - significantly enhancing the operational robustness of PCA9546ADGVR-based designs.

Can multiple PCA9546ADGVR devices be used on the same I²C bus?

Yes, up to eight PCA9546ADGVR devices can coexist on a single I²C bus using the three hardware address pins (A0, A1, A2). Each combination of A0–A2 ties sets a unique 3-bit address offset, resulting in slave addresses from 0x70 to 0x77. This scalability allows hierarchical bus expansion - for example, one PCA9546ADGVR managing four sensor clusters, each with its own downstream PCA9546ADGVR - while maintaining full software control over every channel through standard I²C write/read operations to their respective control registers.

What are the key timing and electrical constraints for reliable PCA9546ADGVR operation?

Reliable PCA9546ADGVR operation requires adherence to I²C Standard-Mode (100 kHz) or Fast-Mode (400 kHz) timing: t_sch ≥ 0.6 µs, t_scl ≥ 1.3 µs, and t_sdh ≥ 0 ns. Electrically, VCC must stay within 2.3–5.5 V, with VPOR (1.6–2.1 V) dictating minimum functional voltage. Input leakage is ≤±1 µA, R_ON ranges from 4 Ω (5 V) to 7 Ω (2.5 V), and total bus capacitance per channel must remain ≤400 pF. Exceeding these limits risks timing violations, increased voltage drop, or incomplete channel switching - all verified in TI's SCPS148G characterization data.