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Microchip Technology MCP23009-E/SS
- Part No.:
- MCP23009-E/SS
- Manufacturer:
- Microchip Technology
- Category:
- I/O Expanders
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
MCP23009-E/SS.pdf
- Description:
- IC XPNDR 3.4MHZ I2C 20SSOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
MCP23009-E/SS from Microchip Technology is an 8-bit I²C-compatible GPIO expander with open-drain outputs, 5.5V-tolerant inputs, and configurable interrupt output. It operates from 1.8V to 5.5V, supports I²C bus speeds up to 3.4 MHz, and delivers 25 mA sink per pin (200 mA total), enabling direct interface with LEDs, switches, and industrial sensors in space-constrained embedded control systems.
For engineers reviewing the MCP23009-E/SS datasheet, MCP23009-E/SS pinout, MCP23009-E/SS application, or MCP23009-E/SS equivalent, this device serves as a low-power, address-configurable I/O extension solution for microcontroller-based designs requiring scalable digital I/O without additional MCU pins - especially where voltage-level flexibility, interrupt-driven event handling, and compact SSOP packaging are critical.
Technical Context
The MCP23009-E/SS implements an I²C slave interface with hardware-addressable 7-bit addressing via a single analog ADDR pin, supporting up to eight devices on one bus using internal FLASH ADC decoding. Its register map includes eleven 8-bit configuration registers (IODIR, IPOL, GPINTEN, DEFVAL, INTCON, IOCON, GPPU, INTF, INTCAP, GPIO, OLAT) for full bidirectional I/O control, polarity inversion, and interrupt-on-change logic.
Each of its eight GPx pins functions as a bidirectional I/O with individually configurable direction, input polarity, interrupt enable, default comparison value, pull-up resistor, and open-drain output drive. The INT pin is software-configurable as active-high, active-low, or open-drain, and interrupts are cleared either by reading INTCAP or GPIO depending on the IOCON.INTCC bit setting.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| I²C Speed | Up to 3.4 MHz - enables high-throughput I/O updates in real-time control loops without MCU bus contention. |
| Supply Voltage | 1.8V to 5.5V - supports mixed-voltage system integration (e.g., 3.3V MCU with 5V peripherals). |
| Input Tolerance | 5.5V-tolerant GPx inputs - allows safe interfacing with higher-voltage signals without level shifters. |
| Sink Current | 25 mA per pin (200 mA total) - drives LEDs, relays, or logic inputs directly without external drivers. |
| Standby Current | 1 µA at −40°C to +85°C - minimizes power in battery-operated or always-on monitoring applications. |
| Interrupt Logic | Configurable interrupt-on-change vs. default-value mismatch - provides flexible event detection for pushbuttons, limit switches, or status flags. |
| Hardware Addressing | Single ADDR pin sets 3-bit I²C address (8 possible devices) - reduces PCB routing complexity versus multi-pin address schemes. |
Pinout & Package
Package: 20-lead SSOP (5.30 mm width), RoHS-compliant, surface-mount.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Power supply input | Connects to main system rail (1.8–5.5 V); powers all internal logic and I/O buffers. |
| VSS | Ground reference | System ground return path; must be low-impedance for stable operation and noise immunity. |
| SCL | I²C clock input | Master-generated clock signal; synchronizes all serial data transfers on the bus. |
| SDA | I²C bidirectional data line | Open-drain shared bus line; requires external pull-up resistor (typically 2.2–10 kΩ). |
| ADDR | Analog hardware address input | Accepts 0–VDD voltage to select one of eight I²C addresses via internal 3-bit FLASH ADC. |
| RESET | Active-low hardware reset | Asynchronous reset that clears all registers to POR defaults; must be pulled high during normal operation. |
| INT | Configurable interrupt output | Open-drain or active-push-pull output signaling GPIO state changes; polarity and clearing mode programmable. |
| GP0–GP7 | Bidirectional I/O terminals | Eight general-purpose pins with 5.5V-tolerant inputs, open-drain outputs, and individual pull-up/interrupt enable. |
Key Features
| Feature | Design Value |
|---|---|
| Single-pin hardware addressing | Reduces board routing overhead and enables up to eight expanders on one I²C bus without address jumpers or DIP switches. |
| Interrupt capture register (INTCAP) | Latches exact port state at interrupt trigger time - eliminates race conditions when polling GPIO after interrupt assertion. |
| Configurable interrupt clearing | Choice between clearing on INTCAP read (preserves GPIO state) or GPIO read (simplifies firmware flow) via IOCON.INTCC bit. |
| Individual input polarity inversion | Per-pin IPOL register bits allow active-low sensors (e.g., N.O. switches) to report logic-high in software without external inverters. |
| Internal pull-up resistors | Software-enabled 20–100 kΩ pull-ups (VDD-dependent) eliminate need for external resistors on switch or button inputs. |
Applications
| Industrial HMI Panel | Smart Home Sensor Hub |
|---|---|
Use Scenario: A compact PLC module adds 8 tactile buttons and 4 status LEDs to a 3.3V ARM Cortex-M4 controller with limited GPIO. IC Role / Device Role / Timing Role: MCP23009-E/SS acts as an I²C-attached parallel I/O extender, managing debounced button reads and LED drive with interrupt-driven edge detection. Use Value: Reduces MCU pin count pressure while enabling responsive, low-latency user interaction via hardware interrupt signaling instead of polling. |
Use Scenario: A Zigbee-connected environmental sensor node integrates temperature, humidity, motion, and door contact inputs across mixed-voltage subsystems. IC Role / Device Role / Timing Role: MCP23009-E/SS aggregates 5V-tolerant dry-contact door sensors and 3.3V motion detector outputs into a unified I²C interface for the host SoC. Use Value: Eliminates discrete level shifters and pull-ups, simplifying BOM and layout while maintaining robust 5.5V input tolerance for legacy security sensors. |
| Medical Wearable UI | Automotive Body Control Module |
Use Scenario: A battery-powered ECG patch uses ultra-low-power sleep modes and wakes only on button press or alert condition. IC Role / Device Role / Timing Role: MCP23009-E/SS monitors two capacitive touch pads and drives haptic feedback LEDs, asserting INT to wake the MCU from deep sleep. Use Value: Achieves sub-µA standby current and precise interrupt timing - extending battery life beyond 6 months on coin cell power. |
Use Scenario: A vehicle interior lighting controller manages 8 LED strings and 4 occupancy sensor inputs in a 12V automotive environment with local 5V regulation. IC Role / Device Role / Timing Role: MCP23009-E/SS interfaces 5V logic-level sensors and drives LED cathodes via open-drain outputs with 25 mA sink capability per channel. Use Value: Enables direct LED sinking without external FETs, reducing component count and thermal footprint in thermally constrained junction boxes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar GPIO expander applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| PCA9554APW,118 | 8-bit I²C expander with push-pull outputs (not open-drain), no ADDR pin (fixed address), no interrupt capture register. | Lacks interrupt-on-change flexibility and voltage-tolerant inputs; suitable only for simple 3.3V-only I/O expansion. | Select PCA9554APW,118 only if open-drain drive, 5.5V tolerance, and interrupt diagnostics are unnecessary. |
| TCA6408AIPWR | 8-bit I²C expander with open-drain outputs, 5.5V-tolerant inputs, but uses 3-pin hardware address (no analog ADDR) and lacks DEFVAL/INTCON register pair for default-value interrupt mode. | Supports fewer I²C devices per bus (max 8 vs. MCP23009's 8 with single pin), and interrupt logic is limited to change-detection only. | Choose TCA6408AIPWR when board layout favors fixed-pin addressing and advanced interrupt modes are not required. |
Compared with PCA9554APW,118 and TCA6408AIPWR, the MCP23009-E/SS uniquely combines analog hardware addressing, interrupt capture, dual-mode interrupt triggering (change vs. default mismatch), and 5.5V-tolerant inputs - making it optimal for designs demanding configurability, diagnostic visibility, and mixed-voltage interoperability.
Availability
MCP23009-E/SS is available at Aetrix Electronics and suitable for industrial HMI panels, smart home sensor hubs, medical wearables, and automotive body control modules requiring stable component supply, long-term lifecycle support, and RoHS-compliant SSOP packaging.
Supply support for MCP23009-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 connectivity solutions, headquartered in Chandler, Arizona, with global design and manufacturing operations.
The MCP23X09 product line was designed specifically for embedded systems needing scalable, low-power, and interrupt-capable parallel I/O expansion over standard serial buses - targeting cost-sensitive, space-constrained applications from consumer electronics to industrial automation.
FAQ
What is the maximum I²C clock frequency supported by the MCP23009-E/SS?
The MCP23009-E/SS supports standard-mode (100 kHz), fast-mode (400 kHz), and high-speed mode (3.4 MHz) I²C operation. At 3.4 MHz, setup and hold times require careful PCB layout and proper pull-up strength; Microchip specifies timing compliance under defined VDD and load conditions per DS20002121C Section 3.0.
How does the ADDR pin determine the I²C address of the MCP23009-E/SS?
The ADDR pin feeds an internal 3-bit FLASH ADC that maps analog voltage (0–VDD) to one of eight discrete 3-bit codes (A2:A1:A0), forming bits 6–4 of the 7-bit I²C slave address (0x20–0x27). Voltage thresholds are VDD-dependent and specified in DS20002121C Figure 1-3; for VDD = 3.3V, midpoints range from 0.206V to 3.094V.
Can the MCP23009-E/SS drive LEDs directly, and what current limits apply?
Yes - the MCP23009-E/SS can drive LEDs directly via its open-drain GPx outputs, sinking up to 25 mA per pin and 200 mA total. Exceeding per-pin or total current ratings risks thermal shutdown or parametric drift; derating is recommended for continuous operation above 15 mA/pin at elevated ambient temperatures.
What is the function of the INTCAP register in the MCP23009-E/SS?
The INTCAP register captures and holds the exact GPIO port state at the moment an interrupt occurs. It is read-only and updated only on interrupt assertion. Reading INTCAP (when IOCON.INTCC = 1) clears the interrupt flag - enabling deterministic, race-free firmware response without missing transient events.
Does the MCP23009-E/SS support hot insertion or live bus connection?
No - the MCP23009-E/SS lacks hot-swap protection circuitry. Connecting or disconnecting the device while VDD or I²C lines are powered may cause latch-up or undefined register states. Power sequencing per DS20002121C Section 2.0 (VDD before SCL/SDA) is mandatory for reliable initialization.
MCP23009-E/SS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Number of I/O:
- 8
- Interface:
- I2C
- Interrupt Output:
- Yes
- Features:
- POR
- Output Type:
- Open Drain
- Current - Output Source/Sink:
- 25mA
- Clock Frequency:
- 3.4 MHz
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
MCP23009-E/SS FAQ
1.How can I place an order for MCP23009-E/SS through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP23009-E/SS on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MCP23009-E/SS reliable?
The price and inventory of MCP23009-E/SS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP23009-E/SS is usually 5 days.
3.What payment methods are accepted for MCP23009-E/SS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP23009-E/SS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MCP23009-E/SS?
MCP23009-E/SS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP23009-E/SS order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MCP23009-E/SS?
For technical support, including MCP23009-E/SS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP23009-E/SS requirements.
6.How does Aetrix verify that MCP23009-E/SS is sourced from the original manufacturer or authorized distributors?
All MCP23009-E/SS products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MCP23009-E/SS meets industry standards.
7.What is the process for return or replacement of MCP23009-E/SS?
All MCP23009-E/SS units undergo pre-shipment inspection (PSI). If there is an issue with MCP23009-E/SS, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MCP23009-E/SS part is unused and in its original packaging.
Return procedure for MCP23009-E/SS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
MCP23009-E/SS Tags
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