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MCP23S18T-E

Public Made by Adom

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Microchip Tech I/O Expanders, SOIC-28-300mil. Pinout cross-checked by two models against the datasheet, KiCad symbol/footprint/3D.

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3D Model

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Symbol & Footprint

Schematic Symbol

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PCB Footprint

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Datasheet

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Contents

README

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MCP23S18T-E

Microchip Tech · I/O Expanders · SOIC-28-300mil

MCP23S18T-E from Microchip Tech, in a SOIC-28-300mil. Pinout and pin descriptions extracted from the manufacturer datasheet (extract_pins, cross-checked by a second model); symbol, footprint, and 3D from KiCad-official CAD.

Pinout

Pin Name Type Function
1 VSS power_in Ground (high current capable).
2 NC unconnected Not connected.
3 GPB0 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
4 GPB1 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
5 GPB2 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
6 GPB3 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
7 GPB4 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
8 GPB5 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
9 GPB6 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
10 GPB7 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
11 VDD power_in Power supply (high current capable), 1.8 V to 5.5 V operating voltage.
12 CS input SPI chip select input.
13 SCK input SPI serial clock input, up to 10 MHz.
14 SI input SPI serial data input.
15 SO output SPI serial data output.
16 RESET input Hardware reset input that must be externally biased.
17 NC unconnected Not connected.
18 INTB output Interrupt output for port B, configurable as active high, active low, or open drain.
19 INTA output Interrupt output for port A, configurable as active high, active low, or open drain.
20 GPA0 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
21 GPA1 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
22 GPA2 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
23 GPA3 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
24 GPA4 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
25 GPA5 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
26 GPA6 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
27 GPA7 bidirectional Bidirectional I/O pin with 5.5 V tolerant input and open-drain output, can be enabled for interrupt on change and/or internal pull-up resistor.
28 NC unconnected Not connected.

Key specifications

Parameter Value
Manufacturer Microchip Tech
Package SOIC-28-300mil
Category Communication Interface Chip/UART/485/232
Pins 28

CAD (KiCad official)

  • Symbol: MCP23S18T-E
  • Footprint: Package_SO:SOIC-28W_7.5x17.9mm_P1.27mm
  • 3D model: SOIC-28-300mil (KiCad packages3D, STEP)
  • 3D model files: mcp23s18t-e-etched.step / mcp23s18t-e-etched.glb carry the MPN laser-etched on the die in a toggleable Adom.LaserEtch group (Fusion-ready); mcp23s18t-e.step / mcp23s18t-e.glb are the bare package body.

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Microchip Tech datasheet (56 pp, sha256 4d2e8ba17e366e46, retrieved 2026-10-27, tier: manufacturer)
  • Extractor: parts-factory 2.0.0 / extract_pins 0.3, primary claude-sonnet-5-5 (text), consensus claude-sonnet-5-5 (agreed), guards: pin_guards 0.1: passed. Pins are checked against the footprint pad set and their cited datasheet pages before publish.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF