MCP23S18T-E/SO

I/o Expanders Overview

The MCP23S18T-E/SO is a Microchip Technology I/O expander featuring a 16-bit bidirectional port with open-drain outputs. It utilizes an SPI interface supporting clock frequencies up to 10 MHz at supply voltages between 2.7V and 5.5V. The device operates within a voltage range of 1.8V to 5.5V and provides 25 mA sink capability per pin, totaling 400 mA. Packaged in a 28-pin SOIC, it includes configurable interrupt outputs and an external reset input.

I/o Expanders Feature Summary

• Provides 16-bit remote bidirectional I/O expansion via SPI interface
• Features open-drain outputs tolerant to 5.5V with high sink current capability
• Supports configurable interrupt outputs for active-high, active-low, or open-drain modes
• Includes polarity inversion register for input data configuration

I/o Expanders Applications

• Systems requiring parallel I/O expansion over serial buses
• Embedded controllers needing additional GPIO ports
• Industrial control interfaces with interrupt-driven inputs

I/o Expanders Procurement Notes

Verify the datasheet revision DS20002103B against the specific manufacturing lot. Confirm that the 'E' suffix denotes the extended temperature grade (-40°C to +125°C) and the '/SO' indicates the 28-pin SOIC package. Ensure the SPI interface requirements match the host controller's timing specifications.

I/o Expanders Selection Notes

Select this component when an SPI interface is preferred over I2C for higher speed communication up to 10 MHz. It is suitable for designs requiring 16 general-purpose I/O lines with open-drain output characteristics. Consider the 28-pin SOIC package constraints for PCB layout and thermal management.

I/o Expanders Part Context

This part belongs to the MCP23X18 family, which also includes the I2C-compatible MCP23018. Both share identical functionality and pinouts except for the serial interface protocol. The MCP23S18 variant specifically replaces the SDA/SCL pins with SPI signals (SI, SO, SCK, CS).

I/o Expanders Replacement Considerations

The MCP23018 serves as a functional equivalent if the system supports I2C instead of SPI. Other Microchip I/O expanders may require significant schematic and software modifications due to differing register maps or interface protocols.