Diodes Incorporated PI4IOE5V9539LEX

Overview

PI4IOE5V9539LEX from Diodes Incorporated is a 16-bit I²C/SMBus GPIO expander with active-low interrupt and reset, 5V-tolerant I/Os, polarity inversion registers, and operation from 2.3V to 5.5V supply. It provides parallel input/output expansion for ACPI power switches, push buttons, LEDs, fans, and sensors in embedded control systems.

For engineers reviewing the PI4IOE5V9539LEX datasheet, PI4IOE5V9539LEX pinout, PI4IOE5V9539LEX application, or PI4IOE5V9539LEX equivalent, key selection criteria include I²C address configurability (A0/A1), open-drain interrupt timing (≤4 µs valid time), 5V I/O tolerance, low standby current (≤1 µA), and dual-package availability (TSSOP-24/TQFN-24).

Technical Context

The device implements two independent 8-bit I/O ports (Port 0 and Port 1), each with configurable direction (via Configuration registers 6/7), polarity inversion (registers 4/5), and input state monitoring. All 16 I/Os support 5V tolerance regardless of VCC level (2.3–5.5V), enabling mixed-voltage system interfacing without level shifters.

Interrupt generation is edge-triggered on input state change and latched until the corresponding Input Port register is read; reset is asynchronous and active-low, forcing all registers and the I²C state machine to default values while preserving VCC. The I²C interface supports Standard Mode (100 kHz) and Fast Mode (400 kHz) with integrated noise filtering on SCL/SDA.

Key Specifications

Pinout & Package

PI4IOE5V9539LEX is offered in TSSOP-24 (173-mil width) package per ordering code L. Pin numbering follows JEDEC MO-153 standard with top-view orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with PCA9539D and TCA6424ARGJR, PI4IOE5V9539LEX uniquely balances 5V I/O tolerance, integrated SCL/SDA noise filtering, and sub-µA standby current-making it optimal for space-constrained, mixed-voltage industrial controllers requiring robust bus operation and ultra-low power.

Availability

PI4IOE5V9539LEX is available at Aetrix Electronics and suitable for ACPI power management, industrial sensor interface, LED status panel control, and fan speed monitoring requiring stable component supply across extended product lifecycles.

Supply support for PI4IOE5V9539LEX 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 integrated circuits, specializing in high-performance, energy-efficient solutions for power management, signal integrity, and connectivity applications.

The PI4IOE5V9539 belongs to Diodes' I/O expansion product line, designed specifically for space-constrained embedded systems needing reliable, low-power GPIO extension with industrial-grade voltage tolerance and noise immunity.

FAQ

What is the maximum sink current per I/O pin on PI4IOE5V9539LEX?

Each I/O pin supports a minimum low-level output current (IOL) of 8 mA at VCC = 2.3 V and VOL = 0.5 V, and 10 mA at VOL = 0.7 V. The absolute maximum sink current per pin is 25 mA, with total device limits of 100 mA per octal port and 200 mA overall, as specified in the Absolute Maximum Ratings table.

Can PI4IOE5V9539LEX operate with a 2.5V supply while interfacing to 5V peripherals?

Yes. All 16 I/O pins are 5V tolerant across the full VCC range (2.3–5.5 V), meaning they safely accept input voltages up to 6.0 V regardless of supply level. This allows direct connection to 5V push buttons, sensors, or logic outputs without external level-shifting components.

How does the interrupt mechanism work when only Port 0 inputs change state?

The open-drain INT pin asserts LOW when any input bit changes state and is configured as an input. Reading the Input Port 0 register clears only the Port 0 interrupt; Port 1 interrupts remain active until Input Port 1 is separately read. This enables selective interrupt handling without cross-port interference.

Is the RESET pin debounced or does it require external hardware filtering?

The RESET pin is asynchronous and not internally debounced. A minimum pulse width of 25 ns is required, but for mechanical switch applications, an external RC filter (e.g., 10 kΩ pull-up + 100 nF capacitor) is recommended to suppress contact bounce and ensure glitch-free reset assertion.