Philips Semiconductors
Clock/calendar with serial I/O
Product specification
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.
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.
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.
3 QUICK REFERENCE DATA
SYMBOL
VDD − VSS1
VDD − VSS2
fosc
PARAMETER
supply voltage, clock (pin 16 to pin 15)
supply voltage, I2C-bus (pin 16 to pin 8)
crystal oscillator frequency
MIN.
1.1
2.5
−
TYP.
−
−
32.768
MAX.
6.0
6.0
−
UNIT
V
V
kHz
4 ORDERING INFORMATION
TYPE NUMBER
PCF8573P
PCF8573T
NAME
DIP16
SO16
PACKAGE
DESCRIPTION
plastic dual in-line package; 16 leads (300 mil)
plastic small outline package; 16 leads; body width 7.5 mm
VERSION
SOT38-4
SOT162-1
2003 Jan 27
3