I/O expanders are integrated circuits (ICs) that are used to provide additional input/output (I/O) capabilities to a microcontroller or other system. I/O expanders are commonly used in applications where a microcontroller or system has a limited number of I/O pins, and additional I/O is needed to interface with sensors, actuators, or other devices. I/O expanders typically communicate with a microcontroller or system using a serial protocol, such as I2C or SPI, and provide a number of additional I/O pins that can be configured as inputs or outputs. Some common features of I/O expanders include:
Support for various serial communication protocols, such as I2C, SPI, UART, and USB
Support for various I/O configurations, such as digital inputs, digital outputs, analog inputs, and pulse-width modulation (PWM) outputs
Support for various operating voltages and power consumption levels, to suit different applications and environments
Support for various package types, such as DIP, SOIC, QFN, and LGA, to suit different applications and systems
Support for various operating temperatures and environmental conditions, such as extended temperature ranges and high-vibration environments.