BinKey

tca6424a-io-expander

2 min read

Important Note

This entire repo was AI created - including all of the data within. The intent was to A) help me with my personal electronics inventory; and B) see how I could use AI to make that process a bit easier. DO NOT TRUST!

Details

The Texas Instruments TCA6424A is a low-voltage 24-bit I2C/SMBus I/O expander designed to expand the number of GPIO pins available on microcontrollers and other digital systems. It provides 24 programmable input/output pins organized as three 8-bit ports, all controlled via a simple 2-wire I2C/SMBus interface. This UQFN-32 package device is ideal for applications requiring GPIO expansion with minimal board space.

Description

The TCA6424A is a parallel-to-serial interface chip that allows a microcontroller with limited GPIO pins to control or monitor up to 24 additional digital I/O lines. Each of the 24 I/O pins can be independently configured as either an input or output. The device communicates with the host microcontroller via the I2C/SMBus protocol, requiring only two signal lines (SDA and SCL) plus power and ground connections.

Specifications

  • Type: 24-bit I2C/SMBus I/O Expander
  • GPIO Pins: 24 (organized as 3 ports of 8 pins each)
  • Interface: I2C/SMBus (2-wire serial communication)
  • Supply Voltage: 1.65V to 5.5V
  • Package: UQFN-32 (Micro QFN, 32-pin)
  • Pin Configuration: 8 pins per side
  • Operating Temperature: -40°C to +85°C
  • I2C Address: Configurable via address pins (multiple devices can be daisy-chained)
  • Features:
    • Programmable input polarity inversion
    • Programmable I/O direction (input or output)
    • Interrupt output pin for input change detection
    • Low power consumption
    • 5V tolerant I/O pins
    • Schmitt trigger inputs

Applications

  • GPIO expansion for microcontrollers with limited I/O
  • Keyboard and button matrix scanning
  • LED control and display drivers
  • Industrial control systems
  • IoT and embedded systems
  • Sensor interface expansion
  • General-purpose digital I/O expansion
  • Home automation systems

Technical Notes

  • Each I/O pin can sink or source up to 25mA
  • Multiple TCA6424A devices can be connected to the same I2C bus using different address configurations
  • The device includes programmable input polarity inversion for each port
  • Interrupt output can be configured to signal when input pins change state
  • Low power consumption makes it suitable for battery-powered applications
  • 5V tolerant I/O allows interfacing with both 3.3V and 5V logic systems
  • Requires pull-up resistors on I2C bus (typically 4.7kΩ)

Pin Configuration

The TCA6424A features 32 pins in a Micro QFN package:

  • 24 GPIO pins (Port 0, Port 1, Port 2 - 8 pins each)
  • 2 I2C interface pins (SDA, SCL)
  • 3 Address pins (A0, A1, A2)
  • 1 Interrupt output pin (INT)
  • Power and ground pins

Tags

TCA6424A, I/O expander, GPIO expansion, I2C, SMBus, 24-bit, Texas Instruments, UQFN-32, microcontroller interface

Graph View

Backlinks