PCF8574 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 100mA 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 PCF8574 device provides general-purpose

remote I/O expansion for most microcontroller families

by way of 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.

Package Information

PART NUMBER

PACKAGE (1)

PACKAGE SIZE(2)

PCF8574

TVSOP (DGV, 20)

5mm × 6.40mm

SOIC (DW, 16)

10.3mm × 10.3mm

PDIP (N, 16)

19.3mm × 9.4mm

TSSOP (PW,20)

6.5mm × 6.4mm

VQFN (RGT, 16)

3mm × 3mm

VQFN (RGY, 20)

4.5mm × 3.5mm

(1)

For more information, see Section 11.

(2)

The package size (length × width) is a nominal value and

includes pins, where applicable.

PCF8574

I2C or SMBus Master

(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

Simplified Schematic

PCF8574

SCPS068K – 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.