Diodes Incorporated PI4MSD5V9543ALEX

Overview

PI4MSD5V9543ALEX from Diodes Incorporated is a 2-channel bidirectional I²C bus switch with integrated interrupt logic and active-low reset, designed for voltage-level translation between mixed-voltage I²C subsystems (1.2 V to 5 V). It supports up to 400 kHz Fast Mode operation, features 5 V-tolerant I/O pins, <1 µA standby current at 3.6 V, and programmable channel selection via I²C register write. Used in multi-sensor hub architectures where isolated downstream buses require independent arbitration and fault recovery.

For engineers reviewing the PI4MSD5V9543ALEX datasheet, PI4MSD5V9543ALEX pinout, PI4MSD5V9543ALEX application, or PI4MSD5V9543ALEX equivalent, key selection criteria include I²C bus isolation capability, interrupt aggregation behavior, reset timing compliance (≥4 ns low pulse), VCC-dependent voltage clamping (Vpass ≤ 2.7 V at VCC = 3.3 V), and SOIC-14W/TSSOP-14L package compatibility with legacy board layouts.

Technical Context

The device implements two independent bidirectional pass-gate channels controlled by an I²C-accessible 8-bit control register; channel enable states persist only after STOP condition recognition to prevent glitching during register writes. Its interrupt logic performs wired-AND aggregation of INT0/INT1 inputs into a single open-drain INT output, enabling master-side interrupt prioritization without hardware OR gates.

Voltage translation is achieved via VCC-referenced pass transistors-no external level shifters needed-where Vpass is clamped to ≤2.7 V when VCC ≤3.3 V, allowing safe interconnection of 5 V masters with 2.5 V or 3.3 V sensor slaves. The internal power-on reset (VPOR = 1.3–1.5 V) and active-low RESET pin (min 4 ns pulse width) ensure deterministic channel deselection on power cycle or bus lockup.

Key Specifications

Pinout & Package

PI4MSD5V9543ALEX is packaged in a 14-pin TSSOP (173 mil wide), RoHS-compliant and Pb-free, with 0.65 mm pitch and exposed pad not present. Thermal resistance θ_JA = 120 °C/W per Diodes Inc. mechanical data.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9548A and PCA9546A, PI4MSD5V9543ALEX uniquely combines dual-channel switching, interrupt aggregation, active-low reset, and 1.65–5.5 V operation with built-in voltage translation-making it optimal for mixed-voltage, interrupt-driven embedded systems requiring deterministic fault recovery.

Availability

PI4MSD5V9543ALEX is available at Aetrix Electronics and suitable for multi-sensor hub architectures, industrial I/O modules, and automotive body control units requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for PI4MSD5V9543ALEX 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and ICs, specializing in high-performance, energy-efficient solutions for industrial, computing, consumer, and automotive markets.

PI4MSD5V9543ALEX belongs to Diodes' I²C interface and bus management product line, engineered specifically for reliable voltage-agnostic I²C subsystem isolation and intelligent interrupt handling in resource-constrained embedded systems.

FAQ

What is the minimum pulse width required on the RESET pin to guarantee channel deselection?

The RESET pin requires a LOW pulse of at least 4 ns to trigger internal state machine reset and clear the control register. This specification is verified under worst-case AC conditions (t_w(rst)L = 4 ns) and ensures deterministic recovery from bus lockup without requiring extended hold times or debouncing circuitry.

Can PI4MSD5V9543ALEX translate between 1.2 V and 5 V I²C buses?

Yes-when VCC is set to 1.8 V, Vpass is clamped to ≤0.9 V, enabling safe 1.2 V slave communication with a 5 V master. External pull-up resistors must match each bus's target voltage (e.g., 5 V pull-up on upstream SCL/SDA, 1.2 V pull-up on SD0/SC0), and bus capacitance must stay ≤400 pF per I²C spec.

How does the interrupt logic handle simultaneous assertions on INT0 and INT1?

INT0 and INT1 are independently latched in bits 4 and 5 of the control register and both drive the open-drain INT output LOW via hardware AND. A read of the control register reveals which channel(s) asserted interrupt, allowing the host to prioritize servicing-no arbitration logic is required in firmware.

Is the PI4MSD5V9543ALEX compatible with standard I²C Fast Mode timing?

Yes-it meets all Fast Mode timing requirements (0–400 kHz) with t_LOW ≥1.3 µs, t_HIGH ≥0.6 µs, and t_r/t_f ≤300 ns under 50 pF load and 1 kΩ pull-up. Propagation delay (t_PD) is 0.3 ns, ensuring negligible impact on setup/hold timing budgets in high-speed implementations.