Diodes Incorporated PI4IOE5V9521XTEX

Overview

PI4IOE5V9521XTEX from Diodes Incorporated is a 2-bit I²C-bus/SMBus GPIO expander IC with interrupt and reset functionality, operating from 2.3V to 5.5V, featuring 5V-tolerant I/Os, active-low open-drain INT output, and active-low RESET input. It provides parallel I/O expansion for ACPI power switches, push buttons, LEDs, and sensors in space-constrained embedded systems.

For engineers reviewing the PI4IOE5V9521XTEX datasheet, PI4IOE5V9521XTEX pinout, PI4IOE5V9521XTEX application, or PI4IOE5V9521XTEX equivalent, key selection criteria include I²C clock support up to 1 MHz, standby current ≤1 µA at 5.5 V, polarity inversion register, noise filtering on SCL/SDA, and UQFN-8 package compatibility with high-density PCB layouts.

Technical Context

The PI4IOE5V9521XTEX implements a two-register I²C slave interface (Input Port, Output Port) with dedicated Polarity Inversion and Configuration registers, enabling per-pin direction control and input logic inversion. Its interrupt generation is edge-triggered on input state change versus Input Port register value, and resets via internal POR (VPOR = 1.16–1.41 V) or external RESET pin (min. 25 ns pulse width).

It supports Standard (100 kHz), Fast (400 kHz), and Fast-Plus (1 MHz) I²C modes with built-in SCL/SDA noise filtering (50 ns spike suppression), and features open-drain INT with 3–13 mA sink capability and 1 µA leakage, ensuring reliable wake-up signaling in low-power systems.

Key Specifications

Pinout & Package

Package: UQFN-8 (1.6 mm × 1.6 mm, 0.4 mm pitch, wettable flank), RoHS-compliant, halogen-free, lead-free.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 2-bit I²C GPIO expander applications.

Compared with PCA9530DP,112 and TCA6408AIPWR, the PI4IOE5V9521XTEX uniquely balances minimal footprint (UQFN-8), ultra-low standby current (≤1 µA), and full interrupt/reset/polarity control in a 2-bit solution-making it optimal for space- and power-constrained dual-signal interfaces.

Availability

PI4IOE5V9521XTEX is available at Aetrix Electronics and suitable for ACPI power management, push-button interface, LED status indication, and fan tach monitoring requiring stable component supply across industrial, computing, and IoT product lifecycles.

Supply support for PI4IOE5V9521XTEX 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 PI4IOE5V9521XTEX belongs to Diodes' Pericom® I²C interface portfolio, designed specifically for compact, low-power I/O expansion in resource-constrained embedded systems where board space and battery life are critical.

FAQ

What is the minimum RESET pulse width required to initialize the PI4IOE5V9521XTEX?

The RESET pin requires a minimum low-time pulse width of 25 ns to trigger a full register and state-machine reset. This asynchronous reset occurs independently of I²C bus activity and restores all registers-including Configuration, Polarity Inversion, Input Port, and Output Port-to their default values without cycling VCC.

Can the PI4IOE5V9521XTEX drive LEDs directly, and what is the maximum sink current per I/O?

Yes, each I/O (P0/P1) can sink up to 10 mA at VCC = 2.3 V and VOL = 0.7 V, scaling to 24 mA at VCC = 4.5 V and VOL = 0.7 V. External current limiting is mandatory: total device sink current must not exceed 50 mA, and individual I/O must be limited to ≤25 mA using series resistors.

How does the interrupt (INT) pin behave when an I/O is reconfigured from output to input?

If an I/O is switched from output to input while its external voltage differs from the stored Input Port register value, a spurious INT assertion occurs. This is due to immediate comparison between physical pin state and register content upon direction change - firmware must read Input Port register after reconfiguration to clear the interrupt condition.

Is the PI4IOE5V9521XTEX compatible with 1 MHz Fast-Plus I²C, and what timing parameters ensure reliability?

Yes, it fully supports Fast-Plus I²C (0–1000 kHz). Reliable operation requires SCL rise/fall times ≤120 ns, bus free time ≥0.5 µs, and SDA setup time ≥50 ns. The internal 50 ns noise filter on SCL/SDA rejects transients that could otherwise corrupt ACK/NACK or data sampling in noisy environments.