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Microchip Technology MCP23S09-E/SO
- Part No.:
- MCP23S09-E/SO
- Manufacturer:
- Microchip Technology
- Category:
- I/O Expanders
- Package:
- 18-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
MCP23S09-E/SO.pdf
- Description:
- IC XPNDR 10MHZ SPI 18SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,170
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Product details
Overview
MCP23S09-E/SO from Microchip Technology is an 8-bit SPI-based I/O expander with open-drain outputs, 5.5V-tolerant inputs, and configurable interrupt output. It operates from 1.8V to 5.5V, supports 10 MHz SPI clock, and delivers 25 mA sink per pin (200 mA total). Used in microcontroller GPIO expansion for industrial HMI panels requiring robust level-shifting and interrupt-driven input monitoring.
For engineers reviewing the MCP23S09-E/SO datasheet, MCP23S09-E/SO pinout, MCP23S09-E/SO application, or MCP23S09-E/SO equivalent, this page provides verified technical context, package-specific pin mapping, real-world use cases, and validated alternative options for embedded system design and BOM optimization.
Technical Context
The MCP23S09-E/SO implements a dedicated SPI slave interface (Mode 0,0 and Mode 1,1), with hardware reset, programmable interrupt polarity (active-high/low/open-drain), and interrupt-on-change logic configurable via GPINTEN, INTCON, and DEFVAL registers. Its 8-bit bidirectional port uses open-drain drivers with individually enabled internal pull-ups.
It features a 11-register memory map including IODIR, IPOL, GPPU, IOCON, and interrupt capture (INTCAP) and flag (INTF) registers. The IOCON register controls sequential/byte addressing mode, INT pin configuration (ODR, INTPOL, INTCC), and enables deterministic register access behavior during polling or burst transfers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Interface | SPI slave (Mode 0,0 and Mode 1,1); no I²C support - requires CS, SCK, SI, SO signals |
| Max Clock Frequency | 10 MHz - enables high-speed GPIO updates in time-critical polling loops or event-driven systems |
| I/O Voltage Tolerance | 5.5V-tolerant inputs - allows direct connection to 3.3V or 5V logic without external level shifters |
| Output Drive | Open-drain, 25 mA sink per pin (200 mA total) - supports driving LEDs, optocouplers, or MOSFET gates directly |
| Supply Range | 1.8V to 5.5V - interoperable across mixed-voltage embedded systems (e.g., 3.3V MCU + 5V peripherals) |
| Interrupt Output | Configurable as active-high, active-low, or open-drain - simplifies integration with diverse host interrupt controllers |
| Standby Current | 1 µA at –40°C to +85°C - suitable for battery-backed or low-power always-on monitoring applications |
Pinout & Package
Package: 18-lead SOIC (7.50 mm wide), RoHS-compliant, surface-mount. Exposed thermal pad not present in SOIC variant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VDD | Power supply input | Primary power rail (1.8–5.5V); high-current capable - must be decoupled near pin with 0.1 µF ceramic capacitor |
| VSS | Ground reference | System ground return path; high-current capable - requires low-impedance connection to PCB ground plane |
| CS | Chip select input | Active-low enable for SPI communication; must be driven low before SCK edge to initiate transaction |
| SCK | SPI clock input | Master-generated clock (up to 10 MHz); idle state configurable (low for Mode 0,0; high for Mode 1,1) |
| SI | SPI data input | Serial data from master; latched on rising SCK edge - carries command, address, and write data |
| SO | SPI data output | Serial data to master; driven on falling SCK edge - returns register reads and interrupt status |
| RESET | Hardware reset input | Active-low asynchronous reset; must be externally biased high (e.g., RC or supervisor IC) for reliable startup |
| INT | Interrupt output | Open-drain or push-pull configurable interrupt signal - asserts when enabled GPIO pins change state or match DEFVAL |
| GP0–GP7 | Bidirectional I/O terminals | 8-bit parallel port; each pin independently configurable as input/output with polarity inversion and pull-up control |
Key Features
| Feature | Design Value |
|---|---|
| Individual pin pull-up control | GPPU register enables/disables internal ~100 kΩ pull-ups per GPx pin - eliminates need for 8 discrete resistors in input-sensing designs |
| Interrupt-on-change with capture | INTCAP register latches port state at interrupt trigger time - enables precise fault logging without race conditions during host read |
| Configurable interrupt clearing | IOCON.INTCC bit selects whether reading INTCAP (1) or GPIO (0) clears interrupt - supports flexible firmware architectures |
| Two SPI clock modes | Supports both Mode 0,0 (SCK idle low) and Mode 1,1 (SCK idle high) - ensures compatibility with diverse MCU SPI peripherals |
| Input polarity inversion | IPOL register flips logic sense of input reads - allows direct connection of active-low switches/sensors without software XOR |
Applications
| Industrial Control Panel | Smart Sensor Node |
|---|---|
|
Use Scenario: Expansion of limited MCU GPIO for membrane keypad scanning and LED status indication in factory HMIs. IC Role / Device Role: SPI-connected remote I/O port providing 8-bit parallel input (key matrix columns) and open-drain output (LED cathodes). Use Value: Eliminates need for external level shifters due to 5.5V-tolerant inputs and supports direct LED drive with 25 mA sink capability per pin. |
Use Scenario: Adding digital input capability to ultra-low-power environmental sensor nodes monitoring door/window contacts and motion detectors. IC Role / Device Role: Low-quiescent-current I/O expander enabling interrupt-driven wake-up from sleep mode upon contact closure. Use Value: 1 µA standby current extends battery life; configurable INT pin triggers MCU wake-up without continuous polling. |
| Programmable Logic Controller I/O Module | Automotive Body Control Unit |
|
Use Scenario: Modular DIN-rail I/O add-on card for PLCs requiring isolated digital inputs and relay driver outputs. IC Role / Device Role: SPI-configurable GPIO hub interfacing between field-side optocouplers and controller-side SPI bus. Use Value: Open-drain outputs interface directly with 24V PLC input circuits; 1.8–5.5V VDD range simplifies power domain bridging. |
Use Scenario: Secondary I/O expansion for BCM managing interior lighting, mirror controls, and seat position sensors. IC Role / Device Role: Robust GPIO extender handling 12V-tolerant switch inputs (via external resistive dividers) and driving local indicator LEDs. Use Value: 5.5V-tolerant inputs withstand automotive load dump transients when used with proper clamping; SOIC package meets AEC-Q200 board-level reliability needs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar I/O expander applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MCP23S17-E/SO | 16-bit I/O, identical SPI interface, same package; adds banked register architecture and interrupt mirroring | Required when >8 GPIOs needed or bank-select logic simplifies firmware; higher pin count but same footprint | Select MCP23S17-E/SO if future scalability or dual-bank isolation (e.g., separate input/output banks) is required. |
| PCA9554APW,118 | I²C-only (400 kHz max), 8-bit, push-pull outputs (not open-drain), no internal pull-ups, fixed address | Suitable only for I²C systems with no interrupt flexibility; lacks DEFVAL/INTCON configurability and 5.5V tolerance | Choose PCA9554APW,118 only for cost-sensitive, non-interrupt, I²C-only designs where 3.3V operation suffices. |
Compared with MCP23S09-E/SO, the MCP23S17-E/SO offers double I/O count and enhanced register organization for complex systems, while the PCA9554APW,118 trades flexibility and voltage robustness for lower unit cost in simple I²C peripheral expansion.
Availability
MCP23S09-E/SO is available at Aetrix Electronics and suitable for industrial HMI panels, smart sensor nodes, PLC I/O modules, and automotive body control units requiring stable component supply and long-term production continuity.
Supply support for MCP23S09-E/SO 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, serving industrial, automotive, and consumer markets with high-reliability silicon and development tools.
The MCP23X09 product line delivers scalable, low-power I/O expansion for resource-constrained microcontrollers, designed specifically for embedded systems needing flexible GPIO extension with deterministic interrupt response and mixed-voltage interoperability.
FAQ
What interface protocol does the MCP23S09-E/SO support?
The MCP23S09-E/SO supports only the SPI serial interface (not I²C). It operates in SPI Modes 0,0 and 1,1, with dedicated CS, SCK, SI, and SO pins. This distinguishes it from the pin-compatible I²C variant MCP23009. The MCP23S09-E/SO requires no address configuration - its SPI opcode is fixed - simplifying multi-device bus design compared to I²C address management.
Does the MCP23S09-E/SO have internal pull-up resistors?
Yes, the MCP23S09-E/SO includes individually controllable internal pull-up resistors on all eight GPx pins, enabled via the GPPU register. Each pull-up is approximately 100 kΩ (typical) and functions regardless of I/O direction setting - usable for both input sensing and wired-OR output configurations. This eliminates external resistor networks in many switch-sensing and bus-wire applications.
Can the MCP23S09-E/SO drive LEDs directly?
Yes, the MCP23S09-E/SO can drive LEDs directly using its open-drain outputs. Each GPx pin sinks up to 25 mA continuously (200 mA total for all pins), supporting common-cathode LED connections with appropriate current-limiting resistors. Its 5.5V-tolerant inputs also allow safe interfacing with 5V LED supply rails when used in sink mode, avoiding level-shifter components.
How is the interrupt output configured on the MCP23S09-E/SO?
The INT pin on the MCP23S09-E/SO is configurable via the IOCON register: ODR bit selects open-drain vs. push-pull mode; INTPOL bit sets active-high/low polarity (when push-pull); and INTCC bit determines whether reading INTCAP or GPIO clears the interrupt. This allows precise tailoring to host MCU interrupt controller requirements without external logic.
What is the operating voltage range of the MCP23S09-E/SO?
The MCP23S09-E/SO operates from 1.8V to 5.5V on VDD, enabling seamless integration into mixed-voltage systems. Its 5.5V-tolerant inputs remain functional even when VDD is at minimum 1.8V - critical for brown-out resilience and interoperability with legacy 5V peripherals. This wide range reduces need for voltage translators in heterogeneous embedded designs.
MCP23S09-E/SO Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- -
- Package/Case:
- 18-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Programmable:
- Not Verified
- Number of I/O:
- 8
- Interface:
- SPI
- Interrupt Output:
- Yes
- Features:
- -
- Output Type:
- Open Drain
- Current - Output Source/Sink:
- 25mA
- Clock Frequency:
- 10 MHz
- Voltage - Supply:
- 1.8V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 18-SOIC
MCP23S09-E/SO FAQ
1.How can I place an order for MCP23S09-E/SO through Aetrix?
Please submit a Request for Quotation (RFQ) for MCP23S09-E/SO 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 MCP23S09-E/SO reliable?
The price and inventory of MCP23S09-E/SO are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MCP23S09-E/SO is usually 5 days.
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We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MCP23S09-E/SO transactions.
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MCP23S09-E/SO orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MCP23S09-E/SO 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 MCP23S09-E/SO?
For technical support, including MCP23S09-E/SO datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MCP23S09-E/SO requirements.
6.How does Aetrix verify that MCP23S09-E/SO is sourced from the original manufacturer or authorized distributors?
All MCP23S09-E/SO 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 MCP23S09-E/SO meets industry standards.
7.What is the process for return or replacement of MCP23S09-E/SO?
All MCP23S09-E/SO units undergo pre-shipment inspection (PSI). If there is an issue with MCP23S09-E/SO, 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 MCP23S09-E/SO part is unused and in its original packaging.
Return procedure for MCP23S09-E/SO:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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