The MCP23016 is not recommended for new designs. Please consider using the MCP23017 or MCP23018 instead. The MCP23016 device provides 16-bit, general purpose, parallel I/O expansion for I2C™Compatible bus applications. It includes high-current drive capability, low supply current and individual I/O configuration. I/O expanders provide a simple solution when additional I/Os are needed for ACPI, power switches, sensors, push buttons, LEDs and so on.