PCF2123

PCF2123 SPI Real time clock/calendar Rev. 6 — 15 July 2013 Product data sheet 1. General description The PCF2123 is a CMOS1 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. 2. Features and benefits  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 C  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 3. Applications  Time keeping application  Battery powered devices  Metering  High duration timers  Daily alarms  Low standby power applications 1. The definition of the abbreviations and acronyms used in this data sheet can be found in Section 22. NXP Semiconductors PCF2123 ...