MCP23009-E/SO

Overview

The MCP23009-E/SO is an 8-bit I/O expander featuring an I²C interface in an 18-lead SOIC package. It operates within a voltage range of 1.8V to 5.5V and supports clock frequencies up to 3.4MHz. The device provides eight bidirectional GPIO pins with open-drain outputs capable of 25mA sink current per pin and 200mA total. Key features include configurable interrupt-on-change, polarity inversion registers, internal pull-up resistors, and hardware address selection via the ADDR pin for multi-device bus configurations.

Feature Summary

• Provides 8-bit remote bidirectional I/O expansion with open-drain outputs tolerant to 5.5V
• Supports high-speed I²C communication with hardware address decoding for up to eight devices on a single bus
• Features configurable interrupt output with interrupt-on-change capability triggered by pin state or default value comparison

Applications

• Key matrix scanning and multi-button panel interfaces
• LED status indicator arrays and lighting control systems
• Sensor enable signal management and digital input acquisition modules

Procurement Notes

Verify the specific suffix 'E/SO' corresponds to the industrial temperature grade (-40°C to +125°C) and the 18-lead SOIC package type. Confirm that the I²C interface requirement aligns with the MCP23009 variant rather than the SPI-based MCP23S09. Ensure compatibility with system voltage levels between 1.8V and 5.5V before procurement.

Selection Notes

Select this component when an I²C interface is preferred over SPI for GPIO expansion. It is suitable for applications requiring up to eight additional digital inputs or outputs with interrupt capabilities. Consider the 18-lead SOIC package constraints regarding PCB space and thermal dissipation. Verify that the required number of I²C addresses does not exceed the eight available through the ADDR pin configuration.

Part Context

This part belongs to the MCP23X09 family, which includes both I²C (MCP23009) and SPI (MCP23S09) variants. The primary distinction lies in the serial interface protocol. The device shares identical register maps and GPIO functionality across the family, allowing for potential interface flexibility if the board design permits alternative connection methods.

Replacement Considerations

The MCP23S09 serves as a functional substitute if the system utilizes an SPI interface instead of I²C. Pinouts differ significantly between the two variants, necessitating schematic and layout modifications. No other direct pin-compatible replacements are documented in the provided source material.