M41T81S_07 Datasheet, PDF (1/31 Pages) STMicroelectronics – Serial access real-time clock with alarms

M41T81S
Serial access real-time clock with alarms
Features
■ Counters for tenths/hundredths of seconds,
seconds, minutes, hours, day, date, month,
year, and century
■ 32KHz crystal oscillator with integrated load
capacitance (12.5pf) which provides
exceptional oscillator stability and high crystal
series resistance operation)
■ Oscillator stop detection (monitors clock
operation)
■ Serial interface supports i²c bus (400kHz
protocol)
■ Ultra-low battery supply current of 0.6μA (typ)
■ 2.0 to 5.5v clock operating voltage
■ Automatic switchover and deselect circuitry
(fixed reference) which provides full operation
in 3.0V applications)
■ V_CC = 2.7 to 5.5V
■ 2.5V ≤ V_PFD ≤ 2.7V
■ Power-down time stamp (ht bit) which allows
determination of time elapsed in battery back-
up
■ Battery low flag
■ Programmable alarm and interrupt function
(valid even during battery back-up mode)
■ Accurate programmable watchdog timer (from
62.5ms to 128s)
■ 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
8
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SO8 (M)
8-pin SOIC
18
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SOX18 (MY)
18-pin (300mil) SOIC
with Embedded Crystal
January 2007
Rev 5
1/31
www.st.com
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