Philips Semiconductors
Product specification
Remote 8-bit I/O expander for I
2
C-bus
1
FEATURES
2
GENERAL DESCRIPTION
PCF8574
•
Operating supply voltage 2.5 to 6 V
•
Low standby current consumption of 10
µA
maximum
•
I
2
C to parallel port expander
•
Open-drain interrupt output
•
8-bit remote I/O port for the I
2
C-bus
•
Compatible with most microcontrollers
•
Latched outputs with high current drive capability for
directly driving LEDs
•
Address by 3 hardware address pins for use of up to
8 devices (up to 16 with PCF8574A)
•
DIP16, or space-saving SO16 or SSOP20 packages.
The PCF8574 is a silicon CMOS circuit. It provides general
purpose remote I/O expansion for most microcontroller
families via the two-line bidirectional bus (I
2
C).
The device consists of an 8-bit quasi-bidirectional port and
an I
2
C-bus interface. The PCF8574 has a low current
consumption and includes latched outputs with high
current drive capability for directly driving LEDs. It also
possesses an interrupt line (INT) which can be connected
to the interrupt logic of the microcontroller. By sending an
interrupt signal on this line, the remote I/O can inform the
microcontroller if there is incoming data on its ports without
having to communicate via the I
2
C-bus. This means that
the PCF8574 can remain a simple slave device.
The PCF8574 and PCF8574A versions differ only in their
slave address as shown in Fig.9.
3
ORDERING INFORMATION
PACKAGE
TYPE NUMBER
NAME
DESCRIPTION
plastic dual in-line package; 16 leads (300 mil)
plastic small outline package; 16 leads; body width 7.5 mm
plastic shrink small outline package; 20 leads; body width 4.4 mm
VERSION
SOT38-1
SOT162-1
SOT266-1
PCF8574P;
PCF8574AP
PCF8574T;
PCF8574AT
PCF8574TS
DIP16
SO16
SSOP20
1997 Apr 02
3
PHILIPS [ NXP SEMICONDUCTORS ]
