Diodes Incorporated PI4IOE5V9554LEX

Overview

PI4IOE5V9554LEX from Diodes Incorporated is an 8-bit I²C/SMBus GPIO expander with interrupt and reset functionality, operating from 2.3 V to 5.5 V supply, featuring 5 V-tolerant I/Os, active-low open-drain INT output, and hardware address pins (A0–A2) enabling up to eight devices on one bus. It serves as a parallel I/O extension for ACPI power switches, push buttons, LEDs, and fan control in embedded power management subsystems.

For engineers reviewing the PI4IOE5V9554LEX datasheet, PI4IOE5V9554LEX pinout, PI4IOE5V9554LEX application, or PI4IOE5V9554LEX equivalent, key selection criteria include I²C clock support up to 400 kHz, polarity inversion register, power-on reset behavior, low standby current (≤700 μA at 5.5 V), and TSSOP-16 package compatibility with standard PCB assembly processes.

Technical Context

The device implements an I²C slave interface with fixed base address (0x20 for PI4IOE5V9554 variant), supporting standard and fast-mode clock frequencies (0–100 kHz / 0–400 kHz). All registers-including Input Port, Output Port, Polarity Inversion, and Configuration-are memory-mapped and accessible via sequential read/write transactions without auto-increment.

Each of the eight bidirectional I/Os can be individually configured as input or output via the Configuration register; inputs feature internal ~100 kΩ pull-ups to VCC and tolerate voltages up to 5.5 V, while outputs drive up to ±10 mA per pin with VOL ≤ 0.7 V at 3.0 V supply. The open-drain INT signal asserts when any configured input changes state and clears upon reading the Input Port register.

Key Specifications

Pinout & Package

TSSOP-16 (173 mil wide) package with exposed pad; lead-free, RoHS 3 and halogen-free compliant. Pin 1 is A0 (address bit 0); pin 16 is VCC. Ground (pin 8) and VCC (pin 16) are placed diagonally to minimize supply noise coupling.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar GPIO expander applications.

Compared with PCA9554APW and TCA6408AIPWR, PI4IOE5V9554LEX uniquely combines 5 V I/O tolerance, polarity inversion, and integrated SCL/SDA noise filtering-making it optimal for compact, mixed-voltage industrial I/O expansion where reliability and design simplicity are prioritized over raw drive strength or reset pin availability.

Availability

PI4IOE5V9554LEX is available at Aetrix Electronics and suitable for ACPI power management, LED status indication, fan tachometer monitoring, and tactile push-button interface applications requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for PI4IOE5V9554LEX 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, energy-efficient components for industrial, computing, and consumer markets.

The PI4IOE5V9554LEX belongs to Diodes' Pericom® I/O expansion portfolio, designed specifically for space-constrained embedded systems needing robust, low-power GPIO extension with industrial-grade ESD and mixed-voltage interoperability.

FAQ

What is the default I/O configuration after power-on reset?

At power-on reset, all eight I/O pins (IO0–IO7) default to high-impedance inputs with internal ~100 kΩ pull-ups to VCC. The Configuration register bits are set to '1', the Output Port register is initialized to 0xFF, and the Polarity Inversion register is cleared to 0x00. This ensures safe, known-startup behavior without external pull resistors.

Can PI4IOE5V9554LEX interface directly with 5 V sensors while powered from 3.3 V?

Yes. All I/O pins are 5 V tolerant up to 5.5 V regardless of VCC level, allowing direct connection to 5 V sensors, switches, or LEDs when VCC = 3.3 V or even 2.3 V. No external level-shifting circuitry is required, simplifying interconnect design and reducing bill-of-materials cost.

How does the interrupt output behave during I/O reconfiguration?

Changing an I/O from output to input may cause a spurious interrupt if the external pin voltage differs from the last-read Input Port value. To avoid this, configure all I/Os before enabling the interrupt, or read the Input Port register immediately after reconfiguration to synchronize internal state and clear any pending assertion.

Is there a difference between PI4IOE5V9554LEX and PI4IOE5V9554ALEX beyond the I²C address?

Yes. PI4IOE5V9554LEX uses base I²C address 0x20 (0100xxx), while PI4IOE5V9554ALEX uses 0x38 (0111xxx), enabling up to 16 total devices (8 of each) on one I²C bus. Functionally identical otherwise-including pinout, timing, electrical specs, and register map-so they are interchangeable in designs using only one variant.