M41T66 Datasheet, PDF (1/33 Pages) STMicroelectronics – Serial access real-time clock with alarms

M41T66
Serial access real-time clock with alarms
Features
■ Counters for tenths/hundredths of seconds,
seconds, minutes, hours, day, date, month,
year, and century
■ 32 KHz crystal oscillator integrating load
capacitance and high crystal series resistance
operation
■ Oscillator stop detection monitors clock
operation
■ Serial interface supports I²C bus (400 kHz)
■ 525 nA timekeeping current at 3 V
■ Low operating current of 35 µA (at 400 kHz)
■ Timekeeping down to 1.0 V
■ 1.3 V to 4.4 V I²C bus operating voltage
– Allows use in lithium ion rechargeable
applications
■ 32 KHz square wave on power-up to drive a
microcontroller in low power mode
■ Programmable (1 Hz to 32 KHz) square wave
■ Programmable alarm with interrupt function
■ Accurate programmable watchdog
(from 62.5 ms to 31 min)
■ Software clock calibration to compensate
deviation of crystal due to temperature
■ Automatic leap year compensation
■ Operating temperature of –40 to 85°C
■ Lead-free 16-pin QFN package
QFN16 (Q) 3 mm x 3 mm
October 2008
Rev 1
1/41
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