Product Overview

PCF8574DWR is an IC bus remote 8-bit I/O expander launched by TI (Texas Instruments) based on the core technology of the PCF8574 series, featuring an SOIC (DW package). It is specifically designed to solve the pain point of insufficient I/O ports in microcontrollers across various embedded systems. This product supports 2.5V-6V wide voltage supply, with a core configuration of 8-bit quasi-bidirectional I/O ports (P0-P7), which combines latched output characteristics and high-current drive capability (maximum low-level output current of 25mA). It can directly drive peripherals such as LEDs and small relays without additional driver chips; it also integrates an open-drain interrupt output (INT) that can real-time respond to rising/falling edge changes of input levels on I/O ports, reducing the polling overhead of the IC bus. With the high compatibility of the SOIC package, standby current as low as 10μA, and wide temperature adaptability of -40℃~+85℃, PCF8574DWR becomes a highly reliable PCF8574DWR expander solution for efficient I/O interface expansion in industrial control, smart home, consumer electronics and other fields.

Key Features

• Efficient IC Bus Expansion, Simplified System Design: PCF8574DWR communicates with microcontrollers via IC two-wire (SCL/SDA), and a single chip can expand 8 I/O ports; it supports setting 8 different slave addresses (decimal 32-39) through A0-A2 address pins, and a single IC bus can cascade 8 devices to expand up to 64 I/O ports. Compared with parallel expansion schemes, it significantly reduces PCB wiring, lowering system complexity and hardware costs.
• Wide Voltage Adaptation + Strong Drive, Full Compatibility: Covering a 2.5V-6V wide supply voltage range, it is compatible with mainstream power supply schemes such as lithium batteries, linear power supplies, and switching power supplies, and can be seamlessly adapted to various microcontrollers including 8051 microcontrollers, STM32, and Arduino; the 8-bit I/O port has a maximum low-level output current (IOL) of 25mA (test condition: VCC=5V, VO=1V), which can directly drive peripherals like LEDs and buzzers, eliminating the need for additional driving components and streamlining the BOM list.
• Low Power Consumption + Interrupt Wake-Up, Adapt to Multi-Scenario Power Supply: The current in standby mode is only 10μA (max, VCC=6V), and the maximum normal operating current (IC clock 100kHz) is 100μA, significantly reducing system power consumption; the open-drain interrupt output (INT) can detect I/O port level changes and trigger microcontroller interrupts, without continuously occupying bus resources, making it especially suitable for battery-powered portable devices and low-power sensor nodes.
• Quasi-Bidirectional I/O Design, Flexible Switching with Zero Threshold: The 8-bit I/O port (P0-P7) adopts quasi-bidirectional mode, defaulting to high level at power-on, without the need to configure data direction control registers, and can flexibly switch between input/output functions according to actual needs; in the high-level state, a current source and strong pull-up circuit are activated, ensuring fast and stable signal rising edges during heavy-load output, adapting to multi-scenario needs such as sensor data acquisition and peripheral state control.
• High Compatibility of SOIC Package, Easy Production and Integration: Adopting an SOIC (DW package) with a 16-pin surface-mount design, the standardized package size (width 10.75mm, length 10.7mm, thickness 2.7mm) is compatible with most automatic placement machines and conventional PCB layouts; the reasonable pin pitch (1.27mm) facilitates both manual soldering and mass production, adapting to the entire process from R&D samples to large-scale mass production.

Technical Specifications

Typical Applications

• Industrial Control Field: In equipment such as PLC expansion modules, industrial sensor data acquisition terminals, and motor control units, PCF8574DWR can expand the I/O ports of microcontrollers via the IC bus to connect multiple sensors (temperature, pressure) and actuators (relays, indicator lights). Its wide temperature range of -40℃~+85℃ adapts to high and low temperature environments in industrial workshops, and the low package thermal impedance of 57℃/W ensures stable heat dissipation under high load. The interrupt output function reduces bus polling overhead, ensuring the real-time performance of industrial data acquisition and control, and improving the efficiency of automated production lines.
• Smart Home Field: Products such as smart switch panels, environmental monitoring gateways, and smart home controllers often face the problem of insufficient I/O ports. PCF8574DWR can expand ports to connect lighting control modules, temperature-humidity sensors, and human infrared detectors. The standby current as low as 10μA is suitable for battery-powered scenarios, and the compact design of the SOIC package can be integrated into miniaturized panels. Meanwhile, the wide voltage characteristic is compatible with the 3.3V/5V power supply of smart home systems, providing a high-integration and low-power I/O expansion solution for smart home products.
• Consumer Electronics Field: In Bluetooth speakers, smart bracelets, and small home appliances (such as coffee machines and air purifiers), PCF8574DWR can expand I/O interfaces to connect LED status indicators, buttons, and small motors. Its 2.5V-6V wide voltage range is compatible with lithium batteries and linear power supplies, the strong drive capability eliminates the need for LED driver chips, and the SOIC package is compatible with the high-density PCB design of consumer electronics, helping products achieve a balance between miniaturization, low cost, and long battery life.
• Medical Equipment Field: Portable medical monitors (such as oximeters and heart rate monitors) and small diagnostic devices have high requirements for the reliability and low power consumption of I/O expansion. PCF8574DWR can expand ports to connect physiological parameter sensors and status indicators. The ultra-low standby current of 10μA significantly extends the battery life of battery-powered devices, the wide voltage range adapts to the stable power supply needs of medical equipment, and the quasi-bidirectional I/O design ensures the accuracy of sensor data acquisition, providing safe and reliable I/O expansion support for medical equipment.
• Automotive Electronics Field: In automotive body control modules (such as window control and in-car lighting adjustment) and on-board diagnostic devices, the wide temperature range of PCF8574DWR can adapt to temperature fluctuations of -40℃~+85℃ inside the car; the IC interface facilitates communication with on-board microcontrollers, the expanded I/O ports can connect multiple actuators and status detection pins, and the interrupt function quickly responds to device status changes. Meanwhile, the high compatibility of the SOIC package adapts to the strict production standards of automotive electronics, improving the stability and safety of on-board systems.

Why Choose PCF8574DWR ？

• High Expansion Efficiency, Low Comprehensive Cost: A single chip realizes 8-channel I/O expansion, and the IC cascading function supports multi-device collaboration without complex parallel circuits; it can directly drive peripherals, reducing the cost of driver chips, and at the same time simplifying PCB wiring and design difficulty, lowering the comprehensive cost of hardware and production links, with cost-effectiveness far exceeding similar I/O expansion schemes.
• Strong Compatibility, Adapt to All Scenarios: The 2.5V-6V wide voltage design covers the power needs of most embedded systems, 8 IC slave addresses support flexible networking, and it can be seamlessly connected with mainstream microcontrollers; the SOIC package is compatible with automatic placement and manual soldering, adapting to the entire process from R&D, small-batch production to large-scale mass production, reducing the cost of scheme replacement.
• Low Power Consumption for Long Battery Life, Good Scenario Adaptability: The ultra-low standby current of 10μA is about 30% lower than similar products (such as PCF8575), which can significantly extend the battery life of battery-powered devices; the interrupt wake-up function reduces system resource occupation, which can not only meet the low-power needs of portable devices but also adapt to the long-term stable operation scenarios of industrial equipment.
• Strong Environmental Adaptability, Full Reliability: The wide operating temperature range of -40℃~+85℃ can cope with harsh environments such as industry and automotive; the low package thermal impedance of 57℃/W ensures controllable chip temperature rise under high load (temperature rise is only about 1.4℃ at 25mA output); it passes strict EMC tests, with strong anti-interference ability, ensuring long-term stable operation of devices.
• Mature Ecosystem + Technical Support, Zero Threshold for Development: As a member of TI's mature product line, PCF8574DWR has complete development materials (datasheet, application notes, reference design) and is compatible with mainstream development tools such as Keil and IAR; TI provides professional technical support to help developers quickly solve design problems, shorten the product development cycle, and accelerate mass production.

SUNTOP COMPANY INTRODUCTION

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