M41ST84W_08 Datasheet, PDF (1/34 Pages) STMicroelectronics – 3.0/3.3 V I2C serial RTC with 44 bytes of NVRAM and supervisory functions

M41ST84W
3.0/3.3 V I²C serial RTC
with 44 bytes of NVRAM and supervisory functions
Features
■ Automatic battery switchover and deselect
– Power-fail deselect, V_PFD = 2.60 V (nom)
– Switchover, V_SO = 2.50 V (nom)
■ 400 kHz I²C serial interface
■ 3.0/3.3 V operating voltage
– V_CC = 2.7 to 3.6 V
■ Ultra-low battery supply current of 500 nA
(max)
■ RoHS compliance
Lead-free components are compliant with the
RoHS directive
Serial RTC features
■ 400 kHz I²C
■ 44 bytes of general purpose NVRAM
■ Counters for:
– Seconds, minutes, hours, day, date, month,
and year
– Century
– 10ths/100ths of seconds
– Clock calibration register allows
compensation for crystal variations over
temperature
■ Programmable alarm with interrupt
– Functions during battery backup mode
■ Power-down timestamp (HT bit)
■ 2.5 to 5.5 V oscillator operating voltage
■ 32 KHz oscillator with integrated load
capacitance (12.5 pF)
■ Battery low flag
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SO16 (MQ)
Microprocessor supervisory features
■ Programmable watchdog timer
– 62.5 ms to 128 s time-out period
■ Power-on reset/low voltage detect output
■ PFI/PFO with 1.25 V reference
Other features
■ Programmable squarewave generator
(1 Hz to 32 KHz)
■ –40°C to +85°C operation
■ Packaged in a 16-lead SOIC
August 2008
Rev 8
1/34
www.st.com
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