PCF8574; PCF8574A
2
Remote 8-bit I/O expander for I C-bus with interrupt
Rev. 5 27 May 2013 Product data sheet
1. General description
The PCF8574/74A provides general-purpose remote I/O expansion via the two-wire
2
bidirectional I C-bus (serial clock (SCL), serial data (SDA)).
2
The devices consist of eight quasi-bidirectional ports, 100 kHz I C-bus interface, three
hardware address inputs and interrupt output operating between 2.5 V and 6 V. The
quasi-bidirectional port can be independently assigned as an input to monitor interrupt
status or keypads, or as an output to activate indicator devices such as LEDs. System
master can read from the input port or write to the output port through a single register.
The low current consumption of 2.5 A (typical, static) is great for mobile applications and
the latched output ports directly drive LEDs.
The PCF8574 and PCF8574A are identical, except for the different fixed portion of the
slave address. The three hardware address pins allow eight of each device to be on the
2
same I C-bus, so there can be up to 16 of these I/O expanders PCF8574/74A together on
2
the same I C-bus, supporting up to 128 I/Os (for example, 128 LEDs).
The active LOW open-drain interrupt output (INT) can be connected to the interrupt logic
of the microcontroller and is activated when any input state differs from its corresponding
input port register state. It is used to indicate to the microcontroller that an input state has
changed and the device needs to be interrogated without the microcontroller continuously
2
polling the input register via the I C-bus.
The internal Power-On Reset (POR) initializes the I/Os as inputs with a weak internal
pull-up 100 A current source.
2. Features and benefits
2
I C-bus to parallel port expander
2 2
100 kHz I C-bus interface (Standard-mode I C-bus)
Operating supply voltage 2.5 V to 6 V with non-overvoltage tolerant I/O held to V
DD
with 100 A current source
8-bit remote I/O pins that default to inputs at power-up
Latched outputs directly drive LEDs
Total package sink capability of 80 mA
Active LOW open-drain interrupt output
Eight programmable slave addresses using three address pins
Low standby current (2.5 A typical)
40 C to +85 C operation
ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM per
JESD22-C101PCF8574; PCF8574A
NXP Semiconductors
2
Remote 8-bit I/O expander for I C-bus with interrupt
Latch-up testing is done to JEDEC standard JESD78 which exceeds 100 mA
Packages offered: DIP16, SO16, SSOP20
3. Applications
LED signs and displays
Servers
Key pads
Industrial control
Medical equipment
PLC
Cellular telephones
Mobile devices
Gaming machines
Instrumentation and test measurement
4. Ordering information
Table 1. Ordering information
Type number Topside mark Package
Name Description Version
PCF8574P PCF8574P DIP16 plastic dual in-line package; 16 leads (300 mil) SOT38-4
PCF8574AP PCF8574AP
PCF8574T/3 PCF8574T SO16 plastic small outline package; 16 leads; body width 7.5 mm SOT162-1
PCF8574AT/3 PCF8574AT
PCF8574TS/3 8574TS SSOP20 plastic shrink small outline package; 20 leads; SOT266-1
body width 4.4 mm
PCF8574ATS/3 8574A
4.1 Ordering options
Table 2. Ordering options
Type number Orderable Package Packing method Minimum Temperature range
part number order
quantity
PCF8574P PCF8574P,112 DIP16 Standard marking 1000 T = 40 C to +85 C
amb
* ICs tube - DSC bulk pack
PCF8574AP PCF8574AP,112 DIP16 Standard marking 1000 T = 40 C to +85 C
amb
* ICs tube - DSC bulk pack
PCF8574T/3 PCF8574T/3,512 SO16 Standard marking 1920 T = 40 C to +85 C
amb
* tube dry pack
PCF8574T/3,518 SO16 Reel 13 Q1/T1 1000 T = 40 C to +85 C
amb
*standard mark SMD dry pack
PCF8574AT/3 PCF8574AT/3,512 SO16 Standard marking 1920 T = 40 C to +85 C
amb
* tube dry pack
PCF8574AT/3,518 SO16 Reel 13 Q1/T1 1000 T = 40 C to +85 C
amb
*standard mark SMD dry pack
PCF8574_PCF8574A All information provided in this document is subject to legal disclaimers. NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 5 27 May 2013 2 of 33