Microchip Technology MCP23008-E/SS

Overview

MCP23008-E/SS from Microchip Technology is an 8-bit I²C-compatible I/O expander IC designed to extend microcontroller GPIO resources in space-constrained embedded systems. It provides bidirectional I/O pins (GP0–GP7), configurable interrupt output (INT), hardware address inputs (A2:A0), and operates from 1.8V to 5.5V across –40°C to +85°C. Used in industrial control panels for remote sensor interface and LED status bank expansion.

For engineers reviewing the MCP23008-E/SS datasheet, MCP23008-E/SS pinout, MCP23008-E/SS application, or MCP23008-E/SS equivalent, key selection criteria include I²C bus speed support (up to 1.7 MHz), low standby current (1 µA max), interrupt-on-change capability with DEFVAL/INTCON register control, and SSOP-20 package compatibility with standard 0.65 mm pitch PCB layouts.

Technical Context

The MCP23008-E/SS implements a fully register-mapped I²C slave interface with eleven 8-bit configuration registers (IODIR, IPOL, GPINTEN, DEFVAL, INTCON, IOCON, GPPU, INTF, INTCAP, GPIO, OLAT) accessible via 7-bit slave address (0x20–0x27). Its interrupt logic supports two mutually exclusive modes: pin-change detection or comparison against programmable DEFVAL register values.

Internal weak pull-up resistors (100 kΩ) per GPIO pin are software-configurable via GPPU register; polarity inversion is supported per-pin via IPOL register; and output latches (OLAT) decouple read-modify-write operations from physical pin states. The device features Power-on Reset (POR) and external RESET input for deterministic initialization.

Key Specifications

Pinout & Package

20-pin SSOP (Shrink Small Outline Package), 0.65 mm lead pitch, body width 5.3 mm, compliant with JEDEC MO-153.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar I/O expansion applications.

Compared with PCA9554APW,118 and TCA6408APWR, the MCP23008-E/SS uniquely delivers three hardware address pins for multi-drop I²C scalability, 1.7 MHz high-speed mode for low-latency control loops, and dual-mode interrupt logic (pin-change or DEFVAL-comparison) essential for robust industrial sensing.

Availability

MCP23008-E/SS is available at Aetrix Electronics and suitable for industrial HMI panels, smart energy meters, automotive body control modules, and IoT sensor aggregators requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MCP23008-E/SS includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microchip Technology Inc. is a leading provider of microcontrollers, analog components, and Flash-IP solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.

The MCP23X08 product line was engineered specifically for cost-sensitive, space-constrained embedded systems needing scalable I/O expansion via industry-standard I²C or SPI interfaces - targeting industrial automation, building controls, and consumer electronics.

FAQ

What is the maximum I²C clock frequency supported by the MCP23008-E/SS?

The MCP23008-E/SS supports I²C operation at 100 kHz, 400 kHz, and up to 1.7 MHz under specified voltage and temperature conditions. At 1.7 MHz, operation is guaranteed only within the 4.5V–5.5V VDD range and –40°C to +125°C ambient, making it suitable for high-throughput industrial control loops where low-latency register access is critical. The MCP23008-E/SS achieves this speed through optimized internal clock synchronization and slew-rate-controlled SDA output.

How does the interrupt-on-change functionality work in the MCP23008-E/SS?

The MCP23008-E/SS interrupt-on-change logic operates in two mutually exclusive modes controlled by the INTCON register: either comparing input states against previous values (default) or against programmable DEFVAL register contents. When enabled via GPINTEN, any qualifying pin transition asserts the INT pin. The INTCAP register captures the exact port state at interrupt trigger time, and the interrupt remains asserted until INTCAP or GPIO is read - ensuring no event loss during host processing. This behavior is fully implemented in the MCP23008-E/SS silicon.

Can the MCP23008-E/SS operate from a 1.8V supply?

Yes, the MCP23008-E/SS is fully specified to operate from 1.8V to 5.5V over the industrial temperature range (–40°C to +85°C). At 1.8V, it supports I²C speeds up to 100 kHz and maintains all functional features including GPIO direction control, interrupt generation, weak pull-up activation, and register read/write operations. Input thresholds scale with VDD, and the internal POR circuit ensures reliable reset across the entire voltage range - confirmed in DS20001919F Section 2.1 DC Characteristics.

What package type does the MCP23008-E/SS use, and is it RoHS compliant?

The MCP23008-E/SS uses a 20-pin SSOP (Shrink Small Outline Package) with 0.65 mm lead pitch and is RoHS compliant per Microchip's official product change notice (PCN# 170201A). The package meets JEDEC MO-153 standards, features matte tin lead finish, and supports standard reflow profiles including J-STD-020D. Pin 1 identifier is marked with a dot; thermal pad is absent - consistent with the SSOP variant documented in DS20001919F page 2.

Does the MCP23008-E/SS include internal pull-up resistors on its GPIO pins?

Yes, the MCP23008-E/SS includes software-configurable internal weak pull-up resistors (100 kΩ typical) on all eight GPIO pins (GP0–GP7). These are enabled or disabled individually via the GPPU register bits. Pull-ups are active only when the corresponding pin is configured as an input (IODIR bit = 1) and have no effect on output pins. This feature eliminates external pull-up resistors in switch/button interfaces and is verified in DS20001919F Section 1.6.7 and Electrical Characteristics table D070.