NXP PCA8574D

Mfr. Part

PCA8574D

Manufacturer

NXP Semiconductors — Y-IC is a trusted quality distributor of NXP brand products and we will provide you with the best products, fast delivery, and responsive service

Detailed Description

8-bit I2C and SMBus GPIO expander with interrupt in SOIC-16 package. Adds eight quasi-bidirectional digital I O lines to any microcontroller using a simple two-wire interface. Wide supply range, low power, and easy hardware addressing for multiple devices on one bus

Key Features

2-wire I2C and SMBus interface supporting Standard and Fast mode up to 400 kHz

Eight quasi-bidirectional I O pins P0 to P7 that can act as input or output without a direction register

Open-drain active-low INT pin to flag input changes to the host without polling

Three hardware address pins A0 to A2 allowing up to eight PCA8574 devices on one bus

Wide supply range 2.3 V to 5.5 V for direct use with 3.3 V and 5 V systems

Low standby current and low-power operation

Each pin can sink current for direct LED drive in many cases

Glitch-free power-up behavior and robust ESD protection

Industrial temperature range typically -40 to +85 °C

Fully RoHS compliant and Pb-free

Key Advantages

Frees up MCU pins by moving buttons, LEDs, and general I O to a small external chip

Simple software model — single byte reads and writes control all eight I O lines

Scales easily — add up to eight expanders per bus using hardware address pins

Cuts wiring and reduces PCB complexity for user interfaces and sensor inputs

Low power and wide voltage support simplify design across many platforms

Interrupt pin reduces firmware overhead by avoiding constant polling

Packaging

Type — SOIC-16 SOP16 with gull-wing leads

Material — epoxy mold compound body with copper leadframe and matte tin lead finish, RoHS and Pb-free

Size — narrow SOIC body approximately 3.9 mm width, ~10.3 mm length, ~1.5 mm height, 1.27 mm lead pitch

Pin configuration — 16 pins total including P0 to P7 GPIO, SDA, SCL, INT open-drain, A0 to A2 address pins, VCC, GND

Thermal characteristics — typical junction-to-ambient thermal resistance ~100 to 130 °C W on a standard PCB, operating temperature -40 to +85 °C

Electrical properties — VCC 2.3 V to 5.5 V, I2C Standard and Fast mode up to 400 kHz, INT active low open-drain, typical standby current in microamps, ESD protection to industry standard, each output can sink current suitable for driving LEDs subject to external limits

Lifecycle

Status — Active and widely used in production designs, not nearing discontinuation

Equivalent and alternative models — verify pinout, addressing, electrical limits, and software differences before substitution

- NXP PCF8574 and PCF8574A legacy I2C 8-bit expanders

- NXP PCA9674 enhanced 8-bit I O expander

- NXP PCA9554 push-pull 8-bit I O expander with direction registers

- Texas Instruments TCA9534 and TCA9554 8-bit I O expanders

- Microchip MCP23008 8-bit I O expander

- onsemi CAT9554 8-bit I O expander

If you need pin-to-pin replacements or drop-in alternatives for your exact board layout, contact our sales team via the Y-IC website for detailed cross references and guidance

Key Application Areas

Expanding MCU GPIO for keypads, switches, push buttons, and indicator LEDs

Human machine interfaces in appliances, printers, and consumer electronics

Sensor input collection and system status monitoring

Industrial controllers, PLC add-ons, and building automation nodes

Server and networking boards needing extra GPIO without changing the main MCU

Embedded systems using I2C buses where pin count and wiring must be minimized

Datasheet

Y-IC hosts the most authoritative and up-to-date datasheet for PCA8574D on our product page. We recommend downloading it here to get full specifications, timing diagrams, pin details, and design guidelines

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