MCP23008-E/SO Microchip 8-Bit I2C I/O Expander, SOIC-18 - Individual Item
OverviewMCP23008-E/SO from Microchip Technology is an 8-bit general-purpose I/O expander with an I2C serial interface. It is used when a microcontroller, processor, or embedded con troller needs more digital input/output lines without moving to a larger host device or adding complex parallel logic.The MCP23008 family provides configurable I/O pins, interrupt capability, polarity inversion, pull-up options, and register-based control through a familiar two-wire interface. The E/SO orderable version is supplied in an 18-lead SOIC package, making it suitable for surface-mount control boards, industrial electronics, instrumentation, and embedded systems that need moderate pin expansion in a compact package.Sale BasisOrder quantity 1 equals one individual MCP23008-E/SO component. This listing is prepared for individual component purchasing rather than as a sealed full tube package.Key Benefits Adds 8 programmable digital I/O channels through an I2C serial bus. Helps reduce host controller pin count and board routing complexity. Supports interrupt-on-change behavior for efficient event detection. Operates across a broad 1.8 V to 5.5 V supply range for common embedded voltage rails. SOIC-18 package is practical for surface-mount production and inspection. Microchip documentation covers both MCP23008 I2C and MCP23S08 SPI family devices for design comparison. Product Features 8-bit remote bidirectional I/O port controlled through I2C. Up to 1.7 MHz I2C clock frequency listed by distributor data. Three hardware address pins allow multiple devices on the same I2C bus. Individual input polarity inversion and interrupt enable control are supported through internal registers. Configurable pull-up resistors are available for input use cases according to the family datasheet. Interrupt output can help a host processor respond to input changes without constant polling. SOIC-18 wide-body surface-mount package matches the E/SO orderable suffix. Technical Specifications Manufacturer Part Number MCP23008-E/SO Manufacturer Microchip Technology Product Category Interface - I/O Expanders Interface I2C Number of I/O 8 Clock Frequency Up to 1.7 MHz listed Supply Voltage 1.8 V to 5.5 V Interrupt Output Yes Output Type Push-pull / configurable I/O behavior per datasheet Mounting Type Surface mount Package / Case 18-SOIC Supplier Device Package 18-SOIC Operating Temperature -40 C to 125 C listed for E suffix family use Sale Unit Individual component Design and Selection NotesUse MCP23008-E/SO when the system already has an I2C bus and needs eight additional general-purpose input/output pins. Designers should review the address-pin configuration, bus pull-up requirements, register map, interrupt configuration, and power-on defaults before final firmware and schematic release. The interrupt output is useful for keypads, switches, simple status lines, and event-driven control logic where polling all inputs would waste processor time.When comparing alternatives, verify the interface type first. MCP23008 uses I2C, while the closely related MCP23S08 uses SPI. Also confirm package, voltage range, temperature grade, address needs, interrupt behavior, and firmware compatibility. Similar I/O expanders can differ in default register state, current drive, addressing, and interrupt logic, so substitution should be checked against the complete datasheet.Applications Microcontroller I/O expansion for compact embedded boards. Keypad, button, switch, and status input collection. LED, relay-driver, and simple control-line expansion when current limits are observed. Industrial control panels, instrumentation, and test fixtures. Sensor interface boards that need more low-speed digital lines. Legacy design support where the MCP23008 family is already qualified. Sourcing and Documentation NotesThe product image is the original Microchip package image retrieved from the manufacturer image service and uploaded unchanged. The attached Product Specification PDF should be reviewed for electrical limits, register behavior, timing diagrams, package dimensions, and recommended operating conditions. Buyers should confirm the exact orderable suffix, voltage rails, firmware register map, and board footprint before using this component in a new or existing design.FAQ What is MCP23008-E/SO best suited for? MCP23008-E/SO is best suited for adding eight configurable digital I/O lines to a microcontroller or processor through an I2C bus. How is MCP23008 different from MCP23S08? MCP23008 uses an I2C interface with three hardware address pins, while MCP23S08 uses SPI with a different address/chip-select arrangement. Firmware and schematic compatibility must be checked before substitution. How many MCP23008 devices can share one I2C bus? The datasheet lists three hardware address pins for MCP23008, allowing up to eight address combinations on the same I2C bus when the system design supports them. What supply voltage range should be checked? Microchip product data lists 1.8 V to 5.5 V operation. Verify I2C pull-up levels, host thresholds, and connected load requirements at the chosen supply voltage. Does MCP23008 support interrupts? Yes. It has a configurable interrupt output that can report input-change events, which helps reduce polling in keypad, switch, status, or simple sensor applications. What does order quantity 1 include? Order quantity 1 includes one individual MCP23008-E/SO component. What package does the E/SO suffix use? The E/SO suffix identifies an 18-lead SOIC package. Confirm the footprint, body width, and pin numbering against the datasheet package drawing. Can MCP23008 drive LEDs or relays directly? Only within the output-current and voltage limits in the datasheet. Use external drivers for loads that exceed the I/O expander ratings. What should firmware engineers verify? Verify register defaults, direction settings, polarity inversion, pull-up configuration, interrupt mode, I2C address pins, and bus speed before release. Where can I find the datasheet? Use the attached Product Specification PDF for MCP23008/MCP23S08 register maps, timing, electrical limits, and package details.