M41T81S Datasheet, PDF (1/29 Pages) STMicroelectronics – Serial Access Real-Time Clock with Alarms

M41T81S
Serial Access Real-Time Clock with Alarms
FEATURES SUMMARY
■ 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
Figure 1. Packages
8
1
SO8 (M)
8-pin SOIC
18
1
SOX18 (MY)*
18-pin (300mil) SOIC
with Embedded Crystal
* Contact local ST sales office for availability.
September 2005
Rev 4.0
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