Interface - I/O Expanders

Image Part Number Description / PDF Quantity Rfq
PCA9535DBR

PCA9535DBR

Texas Instruments

IC I/O EXPANDER I2C 16B 24SSOP

1405

PCF8574DWE4

PCF8574DWE4

Texas Instruments

PARALLEL I/O PORT, 8-BIT, 8 I/O

0

MCP23S18-E/SP

MCP23S18-E/SP

Roving Networks / Microchip Technology

IC EXPANDER SPI 16BIT I/O 28SDIP

375

PCA9673D,112

PCA9673D,112

NXP Semiconductors

IC I/O EXPANDER I2C 16B 24SOIC

390

PCA9536TK,118

PCA9536TK,118

NXP Semiconductors

IC I/O EXPANDER I2C 4B 8HVSON

0

CAT9554HV4I

CAT9554HV4I

CAT9554 - 8-BIT I2C AND SMBUS I/

421

PCA9674PW/S911,118

PCA9674PW/S911,118

NXP Semiconductors

PARALLEL I/O PORT, 8 I/O, CMOS,

14881

PCA9534D,112

PCA9534D,112

NXP Semiconductors

PARALLEL I/O PORT, 8-BIT, 8 I/O

5019

PCA9571GUX

PCA9571GUX

NXP Semiconductors

IC I/O EXPANDER I2C 12XQFN

20171

PCAL6416AHF,128

PCAL6416AHF,128

NXP Semiconductors

IC I/O EXPANDER 16Bit 24HWQFN

0

PCA8575BS,118

PCA8575BS,118

NXP Semiconductors

IC I/O EXPANDER I2C 16B 24HVQFN

7443

TCA9554DWR

TCA9554DWR

Texas Instruments

IC I/O EXPANDER I2C 8BIT 16-SOIC

0

XRA1403IL24-F

XRA1403IL24-F

MaxLinear

IC I/O EXPANDER SPI 16B 24QFN

592

MAX7323ATE+T

MAX7323ATE+T

Maxim Integrated

IC I/O EXPANDER I2C 4B 16TQFN

7500

PCAL6416AEX1Z

PCAL6416AEX1Z

NXP Semiconductors

LOW-VOLTAGE TRANSLATING 16-BIT I

0

PCA9555PWRE4

PCA9555PWRE4

Texas Instruments

IC I/O EXPANDER I2C 16B 24TSSOP

0

IQ82C55AZ

IQ82C55AZ

Intersil (Renesas Electronics America)

IC I/O EXPANDER 24B 44MQFP

0

PCA9574BS,118

PCA9574BS,118

NXP Semiconductors

IC I/O EXPANDER I2C 8B 16HVQFN

8487

MAX7310AEE

MAX7310AEE

Analog Devices, Inc.

MULTI-PORT I/O EXPANDER

0

W83L604G

W83L604G

Nuvoton Technology Corporation America

IC I/O EXPANDER SMBUS 14B 20SSOP

0

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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