Interface - I/O Expanders

Image Part Number Description / PDF Quantity Rfq
PCA8575DB,118

PCA8575DB,118

NXP Semiconductors

IC I/O EXPANDER I2C 16B 24SSOP

434

PCA9554DB

PCA9554DB

Texas Instruments

PCA9554 REMOTE 8-BIT I2C AND SMB

64081

MCP23S17-E/ML

MCP23S17-E/ML

Roving Networks / Microchip Technology

IC I/O EXPANDER SPI 16B 28QFN

2674

TCA9535PWR

TCA9535PWR

Texas Instruments

IC I/O EXPANDER I2C 16B 24TSSOP

0

PCA6107DW

PCA6107DW

Texas Instruments

IC I/O EXPANDER I2C 8B 18SOIC

400

PCA9554DGVR

PCA9554DGVR

Texas Instruments

PCA9554 REMOTE 8-BIT I2C AND SMB

14000

PCA9535HF,118

PCA9535HF,118

NXP Semiconductors

IC I/O EXPANDER I2C 16B 24HWQFN

4334

TCA9534ADWR

TCA9534ADWR

Texas Instruments

IC I/O EXPANDER I2C 8B 16SOIC

1985

PCA9536DR

PCA9536DR

Texas Instruments

IC I/O EXPANDER I2C 4B 8SOIC

7947

PCA9554APWRG4

PCA9554APWRG4

Texas Instruments

IC I/O EXPANDER I2C 8B 16TSSOP

0

PCA9554PWG4

PCA9554PWG4

Texas Instruments

IC I/O EXPANDER I2C 8B 16TSSOP

4050

PCAL6408APWJ

PCAL6408APWJ

NXP Semiconductors

IC I/O EXPANDER 16TSSOP

2027

XRA1403IL24TR-F

XRA1403IL24TR-F

MaxLinear

IC I/O PORT EXPANDER 16 BIT SPI

0

TCA9534DWR

TCA9534DWR

Texas Instruments

IC I/O EXPANDER I2C 8B 16-SOIC

2264

CAT9554AYI-G

CAT9554AYI-G

8-BIT I2C AND SMBUS I/O PORT

30355

MAX7324AEG+

MAX7324AEG+

Maxim Integrated

IC I/O EXPANDER I2C 8B 24QSOP

531200

MAX7329AWE+

MAX7329AWE+

Maxim Integrated

IC I/O EXPANDER I2C 8B 16SOIC

17364492

MAX7300ATI+

MAX7300ATI+

Analog Devices, Inc.

20-PORT OR 28-PORT I/O EXPANDER

1440

MCP23S08-E/ML

MCP23S08-E/ML

Roving Networks / Microchip Technology

IC I/O EXPANDER SPI 8B 20QFN

6

PCA9500PW,112

PCA9500PW,112

Freescale Semiconductor, Inc. (NXP Semiconductors)

IC I/O EXPANDER I2C 8B 16TSSOP

790

Interface - I/O Expanders

1. Overview

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.

2. Main Types & Functional Classification

TypeFunctional CharacteristicsApplication Examples
I2C I/O Expanders2-wire serial interface, addressable ports, low-speed operationConsumer electronics, sensor hubs
SPI I/O ExpandersHigh-speed 3-4 wire interface, daisy-chain capabilityIndustrial control systems, motor drivers
GPIO ExpandersGeneral-purpose digital I/O with configurable direction/pull-upEmbedded systems, LED matrix controllers
UART I/O ExpandersAsynchronous serial communication expansionLegacy device integration, communication modules

3. Structure & Composition

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)

4. Key Technical Specifications

ParameterDescriptionImportance
Channel CountNumber of programmable I/O lines (8-48 channels)Determines peripheral expansion capability
Supply VoltageOperating range (1.65V-5.5V)Compatibility with system power architecture
Communication SpeedUp to 40MHz (SPI), 3.4MHz (I2C)System latency and throughput requirements
Drive StrengthOutput current per pin (4mA-20mA)Peripheral driving capability
Power ConsumptionQuiescent current ( A-nA range)Battery-powered application viability

5. Application Fields

  • Consumer Electronics: Smartphones (button matrix expansion), Wearables
  • Industrial Automation: PLC modules, Sensor networks
  • Automotive Systems: Body control modules, Infotainment interfaces
  • Medical Devices: Portable diagnostic equipment, Patient monitoring
  • Smart Energy: Smart meters, Grid monitoring systems

6. Leading Manufacturers & Products

ManufacturerRepresentative ProductKey Features
Texas InstrumentsPCA955516-bit I2C expander with interrupt generation
NXP SemiconductorsPCAL6416A16-port GPIO with programmable pull-up resistors
Microchip TechnologyMCP2301720MHz SPI interface, 16-channel expansion
STMicroelectronicsSTMPE160016-bit GPIO with touch screen controller interface

7. Selection Guidelines

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

8. Industry Trends

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

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