| Image | Part Number | Description / PDF | Quantity | Rfq |
|---|---|---|---|---|
 |
ROHM Semiconductor |
IC I/O EXPANDER IAC 8B 16VQFN |
43 |
|
I/O Expanders are integrated circuits that provide additional input/output ports for microcontrollers, processors, or other digital systems. They enable peripheral expansion through standardized communication protocols (e.g., I2C, SPI) while maintaining signal integrity and system efficiency. These devices play a critical role in modern electronics by simplifying board design, reducing pin count requirements, and enabling scalable system architectures.
| Type | Functional Characteristics | Application Examples |
|---|---|---|
| I2C I/O Expanders | 2-wire serial interface, addressable ports, low-speed operation | Consumer electronics, sensor hubs |
| SPI I/O Expanders | High-speed 3-4 wire interface, daisy-chain capability | Industrial control systems, motor drivers |
| GPIO Expanders | General-purpose digital I/O with configurable direction/pull-up | Embedded systems, LED matrix controllers |
| UART I/O Expanders | Asynchronous serial communication expansion | Legacy device integration, communication modules |
Typical I/O Expander ICs consist of: - Communication interface controller (I2C/SPI/UART) - Register arrays for configuration/status storage - Programmable port drivers (CMOS/TTL compatible) - Power management circuitry (low-power modes) - Protective structures (ESD protection, overcurrent) Available in standard packages: TSSOP, QFN, SOIC (8-28 pin configurations)
| Parameter | Description | Importance |
|---|---|---|
| Channel Count | Number of programmable I/O lines (8-48 channels) | Determines peripheral expansion capability |
| Supply Voltage | Operating range (1.65V-5.5V) | Compatibility with system power architecture |
| Communication Speed | Up to 40MHz (SPI), 3.4MHz (I2C) | System latency and throughput requirements |
| Drive Strength | Output current per pin (4mA-20mA) | Peripheral driving capability |
| Power Consumption | Quiescent current ( A-nA range) | Battery-powered application viability |
| Manufacturer | Representative Product | Key Features |
|---|---|---|
| Texas Instruments | PCA9555 | 16-bit I2C expander with interrupt generation |
| NXP Semiconductors | PCAL6416A | 16-port GPIO with programmable pull-up resistors |
| Microchip Technology | MCP23017 | 20MHz SPI interface, 16-channel expansion |
| STMicroelectronics | STMPE1600 | 16-bit GPIO with touch screen controller interface |
Key considerations: - Required channel count with future expansion margin - Communication protocol compatibility (existing system bus architecture) - Voltage level matching with peripherals and MCU - Package type suitability for board space constraints - Operating temperature range for industrial/environmental applications - Integrated features (interrupt generation, pull-up resistors, PWM support) - Cost vs performance trade-offs for volume production
Current development directions include: - Higher integration with analog/mixed-signal capabilities - Development of ultra-low-power variants (<1 A standby) - Increased channel density in compact packages (e.g., 24-ch in 3x3mm QFN) - Enhanced functional safety features (IEC 61508 compliance) - Support for emerging interface standards (I3C, enhanced SPI modes) - Embedded intelligence with local GPIO state machines