M41T81S

M41T81S Serial access real-time clock (RTC) with alarms Features ■ Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century ■ 32 KHz crystal oscillator with integrated load capacitance (12.5 pf) which provides exceptional oscillator stability and high crystal series resistance operation) ■ Oscillator stop detection (monitors clock operation) ■ Serial interface supports I2C bus (400 kHz protocol) ■ Ultra-low battery supply current of 0.6 µA (typ) ■ 2.0 to 5.5 V clock operating voltage ■ Automatic switchover and deselect circuitry (fixed reference) which provides full operation in 3.0 V applications) ■ VCC = 2.7 to 5.5 V ■ 2.5 V ≤ VPFD ≤ 2.7 V ■ Power-down time-stamp (HT bit) which allows determination of time elapsed in battery backup ■ Battery low flag ■ Programmable alarm and interrupt function (valid even during battery backup mode) ■ Accurate programmable watchdog timer (from 62.5 ms to 128 s) ■ Software clock calibration (to compensate for crystal deviation due to temperature) ■ Operating temperature of –40 to 85 °C ■ Package options include an 8-lead SOIC or 18-lead embedded crystal SOIC Datasheet − production data 8 1 SO8 8-pin SOIC 18 1 SOX18 18-pin (300 mil) SOIC with embedded crystal May 2012 This is information on a product in full production. Doc ID 10773 Rev 7 1/32 www.st.com 1 Contents Contents M41T81S 1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...