
2003 Jan 27
3
Philips Semiconductors
Product specication
Clock/calendar with serial I/O
PCF8573
1
FEATURES
Serial input/output I2C-bus interface for minutes, hours,
days and months
Additional pulse outputs for seconds and minutes
Alarm register for presetting a time for alarm or remote
switching functions
On-chip power fail detector
Separate ground pin for the clock allows easy
implementation of battery back-up during supply
interruption
Crystal oscillator control (32.768 kHz)
Low power consumption.
2
GENERAL DESCRIPTION
The PCF8573 is a low threshold, CMOS circuit that
functions as a real time clock/calendar. Addresses and
data are transferred serially via the two-line bidirectional
I2C-bus.
The IC incorporates an addressable time counter and an
addressable alarm register for minutes, hours, days and
months. Three special control/status flags, COMP, POWF
and NODA, are also available. Back-up for the clock during
supply interruptions is provided by a 1.2 V nickel cadmium
battery. The time base is generated from a 32.768 kHz
crystal-controlled oscillator.
3
QUICK REFERENCE DATA
4
ORDERING INFORMATION
SYMBOL
PARAMETER
MIN.
TYP.
MAX.
UNIT
VDD VSS1
supply voltage, clock (pin 16 to pin 15)
1.1
6.0
V
VDD VSS2
supply voltage, I2C-bus (pin 16 to pin 8)
2.5
6.0
V
fosc
crystal oscillator frequency
32.768
kHz
TYPE NUMBER
PACKAGE
NAME
DESCRIPTION
VERSION
PCF8573P
DIP16
plastic dual in-line package; 16 leads (300 mil)
SOT38-4
PCF8573T
SO16
plastic small outline package; 16 leads; body width 7.5 mm
SOT162-1