Microchip 16-Bit I/O Expander SPI 1.8V-5.5V SSOP-28

The Microchip 16-Bit I/O Expander adds 16 general-purpose parallel I/O lines to microcontroller systems that use a Serial Peripheral Interface (SPI). It provides a flexible way to add digital pins for controlling and monitoring external devices.

Overview

The device is organised as two 8-bit ports, PORTA and PORTB, and can be configured in software to operate in either 8-bit or unified 16-bit mode. Multiple 8-bit configuration registers set the direction (input or output), polarity and data for each I/O pin. A system master can dynamically enable any I/O as an input or output by writing to the I/O configuration registers, while input and output data are maintained in corresponding registers.

Key Features

• SPI Serial Interface: High-speed, full-duplex communication with the system master, supporting data rates up to 1.7MHz.
• Cascading Capability: Up to eight devices can be connected on the same SPI bus, allowing expansion of up to 128 additional I/O lines from a single microcontroller.
• High Drive Capability: Each I/O pin can sink or source up to 25mA.
• Wide Operating Voltage: Supports a supply voltage range from 1.8V to 5.5V, compatible with low-voltage and legacy 5V logic systems.
• Polarity Control: The polarity of the input port register can be inverted via a dedicated register.
• Compact Package: Housed in an SSOP-28 package and rated for an extended industrial temperature range from -40°C to +125°C.

Specifications

• Package: SSOP-28
• Dimensions (W x D x H): 3.3 x 1.5 x 4.3
• Weight: 0.483 gm

Choose this I/O expander when a microcontroller project needs additional digital pins over SPI. Its 1.8V to 5.5V operating range and 25mA per-pin drive make it suitable for interfacing with LEDs, relays and other peripherals.