Diodes Incorporated PI4MSD5V9545ALE

Overview

PI4MSD5V9545ALE from Diodes Incorporated is a quad 1-of-4 bidirectional I²C bus switch with integrated interrupt logic, reset control, and voltage-level translation across 1.2 V to 5.5 V domains. It supports up to 400 kHz Fast Mode I²C operation, features 5 V-tolerant I/O pins, and provides channel-selectable isolation with <10 µA standby current at 3.6 V. It is used in multi-voltage system management where microcontrollers must arbitrate communication among heterogeneous I²C peripherals (e.g., sensors, EEPROMs, PMICs) on separate voltage rails.

For engineers reviewing the PI4MSD5V9545ALE datasheet, PI4MSD5V9545ALE pinout, PI4MSD5V9545ALE application, or PI4MSD5V9545ALE equivalent, key selection criteria include its 4-channel interrupt aggregation capability, programmable channel enable via I²C register, active-low reset recovery for stuck-bus conditions, and verified voltage translation performance across 1.2 V/1.8 V/2.5 V/3.3 V/5 V combinations without external level shifters.

Technical Context

The device implements four independent bidirectional pass-gate switches controlled by an internal I²C-addressable 8-bit control register, where bits B0–B3 select active downstream channels (SCx/SDx), and bits B4–B7 reflect real-time interrupt status per channel. Its architecture enables hot insertion and glitch-free power-up via internal POR and external RESET pin, both forcing all channels to deselected state.

Each channel isolates capacitance when disabled (≤5 pF I/O capacitance), while enabled channels exhibit low ON-resistance (4–70 Ω depending on VCC and load), enabling signal integrity preservation up to 400 kHz. The INT output functions as a wired-AND of four open-drain interrupt inputs (INT0–INT3), allowing centralized interrupt handling without polling.

Key Specifications

Pinout & Package

Package: 20-pin TSSOP (173 mil width), RoHS-compliant, lead-free, halogen- and antimony-free "Green" construction.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TCA9545A and PCA9546A, PI4MSD5V9545ALE delivers deterministic interrupt response and hardware-assisted bus recovery-critical for real-time diagnostics and fault-tolerant embedded systems where software-only solutions introduce unacceptable latency or reliability risk.

Availability

PI4MSD5V9545ALE is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and server management applications requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant manufacturing.

Supply support for PI4MSD5V9545ALE 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 analog ICs, specializing in high-reliability power management, signal integrity, and interface solutions for industrial, automotive, and computing markets.

The PI4MSD5V9545ALE belongs to Diodes' Pericom® interface product line, designed specifically for robust, multi-voltage I²C system expansion with built-in fault resilience and simplified firmware integration.

FAQ

Does PI4MSD5V9545ALE support hot-plug insertion of downstream I²C peripherals?

Yes. The device supports hot insertion due to its glitch-free power-up behavior, no-stuck-state default (all channels deselected at POR), and 5 V-tolerant I/O pins. When a downstream peripheral is inserted while powered, the switch prevents bus contention and ensures SDA/SCL remain high-impedance until explicitly enabled via I²C control register write.

How does voltage translation work without external components?

Voltage translation is achieved through pass-gate transistors whose conduction is limited by the VCC supply voltage. For example, setting VCC = 3.3 V caps the maximum passed voltage (Vpass) to ~2.8 V, enabling safe communication between a 5 V upstream master and 3.3 V or lower downstream slaves-no external level shifters or clamping diodes are needed.

Can INT0–INT3 be used as general-purpose inputs if interrupt functionality is not required?

Yes. The INT0–INT3 pins are standard CMOS inputs with defined VIH/VIL thresholds and ±1 µA leakage. If unused, they must be tied to VCC via a pull-up resistor to prevent floating states; they can then serve as auxiliary GPIOs for status monitoring or configuration detection in space-constrained designs.

What happens to downstream buses when a channel is deselected?

When a channel is deselected, its SCx/SDx pins enter high-impedance state with ≤5 pF capacitance to ground, effectively isolating that segment from the upstream bus. This prevents capacitive loading, signal reflection, and unintended current paths-preserving signal integrity and enabling true bus segmentation.