PCF8574A Remote 8-Bit I/O Expander for I2C Bus

1 Features

• Low standby-current consumption of 10μA max

• I2C to parallel-port expander

• Open-drain interrupt output

• Compatible with most microcontrollers

• Latched outputs with high-current drive capability

for directly driving LEDs

• Latch-up performance exceeds 100 mA Per JESD

78, Class II

2 Applications

• Telecom shelters: filter units

• Servers

• Routers (telecom switching equipment)

• Personal computers

• Personal electronics

• Industrial automation

• Products with GPIO-Limited Processors

3 Description

This 8-bit input/output (I/O) expander for the two-line

bidirectional bus (I2C) is designed for 2.5V to 6V VCC

operation.

The PCF8574A device provides general-purpose

remote I/O expansion for most microcontroller families

via the I2C interface [serial clock (SCL), serial data

(SDA)].

The device features an 8-bit quasi-bidirectional I/O

port (P0–P7), including latched outputs with high-

current drive capability for directly driving LEDs. Each

quasi-bidirectional I/O can be used as an input or

output without the use of a data-direction control

signal. At power on, the I/Os are high. In this mode,

only a current source to VCC is active.

Device Information

PART NUMBER

PACKAGE(1)

BODY SIZE (NOM)

PCF8574A

VQFN (20)

4.50mm × 3.50mm

PDIP (16)

19.30mm × 6.35mm

SOIC (16)

10.30mm × 7.50mm

TSSOP (20)

6.50mm × 4.40mm

TVSOP (20)

5.00mm × 4.40mm

(1)

For all available packages, see the orderable addendum at

the end of the data sheet.

PCF8574A

I2C or

SMBus Commander

(e.g. Processor)

Peripheral Devices

RESET, ENABLE,

or control inputs

INT or status

outputs

LEDs

SDA

SCL

INT

A0

A1

A2

GND

VCC

P0

P1

P2

P3

P4

P5

P6

P7

PCF8574A

SCPS069H – JULY 2001 – REVISED SEPTEMBER 2024

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.