MCP23009T-E/SS

Overview

The MCP23009T-E/SS is an 8-bit I/O expander featuring an I2C interface, housed in a 20-lead SSOP package. It operates within a supply 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, internal pull-up resistors, polarity inversion, and hardware address selection via the ADDR pin for multi-device bus configurations.

Feature Summary

• Supports high-speed I2C communication with configurable slave addressing
• Provides eight bidirectional general-purpose I/O pins with open-drain output capability
• Features configurable interrupt outputs triggered by pin state changes or default value comparisons
• Includes internal pull-up resistors and input polarity inversion registers

Applications

• Expanding microcontroller I/O capabilities in embedded systems
• Controlling LED arrays and status indicators
• Scanning keypads and button matrices
• Managing sensor enable signals and digital inputs

Procurement Notes

Verify the specific suffix 'T' indicates tape-and-reel packaging when ordering. Confirm the '-E' designation aligns with the required industrial temperature range specifications. Ensure the SSOP package dimensions match the target PCB footprint constraints. Cross-reference the manufacturer part number with authorized distributors to guarantee component authenticity and traceability.

Selection Notes

Select this model over the MCP23S09 variant if an I2C interface is preferred over SPI. Consider the MCP23017 if sixteen I/O ports are required instead of eight. Evaluate the power consumption requirements against the standby current specifications at the intended operating temperature. Verify that the I2C bus speed requirements do not exceed the maximum supported frequency of 3.4MHz.

Part Context

This component belongs to the MCP23X09 family of I/O expanders, which also includes the SPI-based MCP23S09. The family shares identical register maps and functional behaviors, differing only in the serial communication protocol. The MCP23009 series is designed for applications requiring simple parallel I/O expansion over standard two-wire interfaces.

Replacement Considerations

Direct substitutes include other MCP23009 variants with different packages such as MCP23009-E/SO or MCP23009-E/MG. Ensure any replacement maintains the same I2C interface and pinout compatibility. Verify that alternative packages meet the thermal and mechanical requirements of the design.

FAQ

How many devices can be addressed on a single I2C bus using the ADDR pin?

Up to eight devices can be connected to the same I2C bus by configuring the analog voltage levels on the ADDR pin.

What is the default state of the GPIO pins upon power-up?

All GPIO pins default to input mode with the corresponding direction bits set to logic one in the IODIR register.

Can the interrupt output be configured as open-drain?

Yes, the INT pin can be configured as active-high, active-low, or open-drain via the IOCON register settings.