Diodes Incorporated PI4MSD5V9542ALEX

Overview

PI4MSD5V9542ALEX from Diodes Incorporated is a 2-channel bidirectional I²C-bus multiplexer with integrated interrupt logic, designed to isolate and route SDA/SCL signals between one upstream master and two downstream slave buses. It supports voltage translation across 1.2 V, 1.8 V, 2.5 V, 3.3 V, and 5 V domains, features 5 V-tolerant I/O, operates from 1.65 V to 5.5 V supply, and delivers ≤9 Ω typical Ron at 4.5–5.5 V - enabling robust multi-voltage I²C expansion in server management controllers.

For engineers reviewing the PI4MSD5V9542ALEX datasheet, PI4MSD5V9542ALEX pinout, PI4MSD5V9542ALEX application, or PI4MSD5V9542ALEX equivalent, key selection criteria include its dual-interrupt input handling (INT0/INT1), AND-gated open-drain INT output, programmable channel selection via I²C register write, power-up default deselection, and 400 kHz Fast Mode support - all critical for fault-aware sensor hub and hot-pluggable module designs.

Technical Context

The device implements a 1-of-2 analog pass-gate multiplexer controlled by an on-chip I²C state machine; channel selection is latched only after a STOP condition, preventing bus glitches during reconfiguration. Its VCC-referenced pass gates enable true bidirectional level shifting without direction pins or external translators.

Interrupt logic operates independently of channel selection: INT0 and INT1 monitor downstream devices continuously, and their states are captured in bits 5 and 4 of the read-accessible control register. The open-drain INT output asserts low when either input is active, allowing master firmware to identify interrupt sources before switching channels.

Key Specifications

Pinout & Package

PI4MSD5V9542ALEX is housed in a 14-pin TSSOP package (JEDEC MO-153, 5.0 mm × 4.4 mm × 1.2 mm), optimized for high-density PCB layouts and automated assembly. Pin pitch is 0.65 mm; thermal pad is not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9548A and PCA9546A, PI4MSD5V9542ALEX uniquely integrates dual interrupt inputs, AND-gated output, and native multi-voltage translation in a 2-channel form factor - delivering lower system-level BOM cost and faster interrupt response in mixed-voltage embedded control applications.

Availability

PI4MSD5V9542ALEX is available at Aetrix Electronics and suitable for server baseboard management, industrial sensor hubs, hot-pluggable module interfaces, and multi-rail power management systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for PI4MSD5V9542ALEX 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 semiconductor company specializing in discrete, analog, and mixed-signal ICs for power management, signal integrity, and connectivity applications - serving automotive, industrial, computing, and consumer markets.

The PI4MSD5V9542ALEX belongs to Diodes' I²C interface and signal conditioning product line, engineered specifically for reliable, low-latency expansion of I²C buses in thermally constrained, multi-voltage embedded systems.

FAQ

What is the function of the VCC pin beyond powering the device?

VCC sets the maximum pass voltage (Vpass) for the internal MOSFET pass gates, directly determining the upper voltage limit translated to downstream buses. For example, with VCC = 3.3 V, Vpass max ≈ 2.8 V - enabling safe interfacing of 3.3 V upstream logic with 2.5 V or 1.8 V downstream slaves without overvoltage risk.

How does the interrupt logic behave when no channel is selected?

INT0 and INT1 are monitored continuously regardless of channel selection state; their logic levels are captured in bits 5 and 4 of the control register upon read. The INT output reflects the logical AND of both inputs, so it asserts low if either interrupt input is active - enabling interrupt detection prior to channel activation.

Can unused interrupt inputs be left floating?

No - unused INT0 or INT1 pins must be pulled HIGH to VCC via a resistor (typically 10 kΩ). Floating interrupt inputs cause indeterminate logic states, potentially triggering false interrupts or violating input leakage specifications, leading to unpredictable control register behavior.

What happens during power-up, and how is the device initialized?

An internal power-on reset (POR) holds the device in reset until VCC reaches 1.3–1.5 V (VPOR), then initializes the control register to 0x00 (all channels deselected) and resets the I²C state machine. This guarantees no unintended channel activation or bus glitches at startup - a requirement for fail-safe system initialization.