Texas Instruments PCA9544APWRG4

Overview

PCA9544APWRG4 from Texas Instruments is a low-voltage 4-channel I²C and SMBus multiplexer with integrated interrupt logic, designed to resolve slave address conflicts by enabling time-multiplexed access to four downstream I²C buses. It supports bidirectional voltage-level translation between 1.8-V, 2.5-V, 3.3-V, and 5-V domains, operates from 2.3 V to 5.5 V, delivers <10 Ω typical switch-on resistance, and handles up to 400-kHz clock frequency - deployed in server backplanes and telecom switching equipment.

For engineers reviewing the PCA9544APWRG4 datasheet, PCA9544APWRG4 pinout, PCA9544APWRG4 application, or PCA9544APWRG4 equivalent, key selection criteria include its 20-pin TSSOP (PW) package, active-low interrupt aggregation (INT = INT3 ∧ INT2 ∧ INT1 ∧ INT0), programmable channel selection via I²C control register, and support for hot insertion without bus glitches.

Technical Context

The PCA9544APWRG4 implements a single-pole, four-throw (SP4T) bidirectional translating switch architecture controlled by an 8-bit I²C register, where bits B0–B2 select one of four downstream SCL/SDA channels while bits INT3–INT0 reflect real-time interrupt status. Its pass-gate design uses VCC as a voltage-limiting reference, enabling level-shifting without external components.

Interrupt logic performs wired-AND aggregation: the open-drain INT output asserts low when any of the four active-low INTn inputs is pulled low, with 4-μs valid propagation delay and 2-μs reset delay. Power-on reset initializes all channels to deselected state and clears the I²C state machine when VCC crosses VPORR (1.5 V typ) rising or VPORF (1.0 V typ) falling.

Key Specifications

Pinout & Package

PCA9544APWRG4 is packaged in a 20-pin TSSOP (PW) measuring 6.50 mm × 4.40 mm, with exposed thermal pad for enhanced heat dissipation in dense PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9544APWR, PCA9544APWRG4 shares full functional equivalence but differs in packaging date code and environmental compliance labeling; versus PCA9548APWR, it trades channel count for reduced standby current and tighter layout fit in space-constrained server management modules.

Availability

PCA9544APWRG4 is available at Aetrix Electronics and suitable for server backplane management, telecom switching equipment, and factory automation I/O hubs requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for PCA9544APWRG4 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 company headquartered in Dallas, Texas, delivering analog and embedded processing solutions for industrial, automotive, and communications markets.

The PCA9544A product line was developed to solve I²C address collision and mixed-voltage interoperability challenges in high-density embedded systems - targeting server, networking, and industrial control applications where bus scalability and signal integrity are critical.

FAQ

What is the package type and dimensions of the PCA9544APWRG4?

The PCA9544APWRG4 uses a 20-pin TSSOP (PW) package measuring 6.50 mm × 4.40 mm with a standard 0.65-mm lead pitch. This compact surface-mount outline supports high-density PCB layouts in space-constrained applications like server mezzanine cards and telecom line cards. The device does not include a thermal pad in this variant.

Does the PCA9544APWRG4 support voltage translation between different I²C bus voltages?

Yes, the PCA9544APWRG4 supports bidirectional voltage-level translation among 1.8-V, 2.5-V, 3.3-V, and 5-V I²C buses. Its pass-gate architecture uses VCC as the upper voltage limit, allowing each downstream channel (SDn/SCn) to operate at its native voltage - provided external pull-up resistors are connected to their respective bus supply rails.

How does interrupt aggregation work on the PCA9544APWRG4?

The PCA9544APWRG4 features four active-low interrupt inputs (INT0–INT3), one per downstream channel, and a single active-low interrupt output (INT). The INT pin functions as a wired-AND of all four inputs: it asserts low whenever any INTn input is pulled low. This allows a single MCU GPIO to monitor fault conditions across four isolated I²C segments.

What is the power-on reset behavior of the PCA9544APWRG4?

Upon power application, the PCA9544APWRG4 enters a reset state until VCC rises above VPORR (1.5 V typical). At that point, the I²C state machine and control register initialize to default values - all channels deselected (B2–B0 = 000) and interrupt flags cleared. This ensures glitch-free startup and prevents unintended bus arbitration before system stabilization.

Can multiple PCA9544APWRG4 devices share the same I²C bus?

Yes, up to eight PCA9544APWRG4 devices can coexist on a single upstream I²C bus using hardware-addressable pins A0–A2. These three inputs allow configuration of slave addresses from 0x70 to 0x77, enabling hierarchical bus expansion - for example, one device managing four sensor zones, another handling four power modules, all under one master controller.