描述 Description

The PCF2123 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power applications. Data is transferred serially via a Serial Peripheral Interface (SPI-bus) with a maximum data rate of 6.25 Mbit/s. An alarm and timer function is also available providing the possibility to generate a wake-up signal on an interrupt pin. An offset register allows fine tuning of the clock.

特性 Features

Real time clock provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768 kHz quartz crystal
Low backup current while running: typical 100 nA at VDD = 2.0 V and Tamb = 25 ℃
Resolution: seconds to years
Watchdog functionality
Freely programmable timer and alarm with interrupt capability
Clock operating voltage: 1.1 V to 5.5 V
3 line SPI-bus with separate, but combinable data input and output
Serial interface at VDD = 1.8 V to 5.5 V
1 second or 1 minute interrupt output
Integrated oscillator load capacitors for CL = 7 pF
Internal Power-On Reset (POR)
Open-drain interrupt and clock output pins
Programmable offset register for frequency adjustment

應用 Application

Time keeping application
Battery powered devices
Metering
High duration timers
Daily alarms
Low standby power applications