Features
 For all new designs use M41T81S
 Counters for tenths/hundredths of seconds,
seconds, minutes, hours, day, date, month,
year, and century
 32 KHz crystal oscillator integrating load
capacitance (12.5 pF) providing exceptional
oscillator stability and high crystal series
resistance operation
 Serial interface supports I2C bus (400 kHz
protocol)
 Ultra-low battery supply current of 0.6 ΜA
(typ at 3 V)
 2.0 to 5.5 V clock operating voltage
 Automatic switchover and deselect circuitry (for
3 V application select M41T81S datasheet)
 Power-down time stamp (HT bit) allowing
determination of time elapsed in battery
backup
 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
crystal deviation due to temperature
 Operating temperature of –40 to 85 °C
 ECOPACK® package available