STMicroelectronics M41T81SMY6F

Description
The M41T81SST is a serial access real-time clock (RTC) with alarms. It features counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century. The RTC also has a 32 KHz crystal oscillator with integrated load capacitance (12.5 pF), which provides exceptional oscillator stability and high crystal series resistance operation.
The M41T81SST supports the I²C bus (400 kHz protocol) and has an ultra-low battery supply current of 0.6 μA (typ). It operates from a 2.0 to 5.5 V clock operating voltage and has automatic switchover and deselect circuitry (fixed reference), which provides full operation in 3.0 V applications.
The RTC also has a power-down time-stamp (HT bit) which allows determination of time elapsed in battery backup, a battery low flag, and a programmable alarm and interrupt function (valid even during battery backup mode). It also has an accurate programmable watchdog timer (from 62.5 ms to 128 s) and software clock calibration (to compensate for crystal deviation due to temperature).
The M41T81SST operates over a temperature range of -40 to 85 °C and is available in an 8-lead SOIC or 18-lead embedded crystal SOIC package.

Features
Counters for tenths/hundredths of seconds, seconds, minutes, hours, day, date, month, year, and century
32 KHz crystal oscillator with integrated load capacitance (12.5 pF)
Oscillator stop detection
Serial interface supports I²C bus (400 kHz protocol)
Ultra-low battery supply current of 0.6 μA (typ)
2.0 to 5.5 V clock operating voltage
Automatic switchover and deselect circuitry (fixed reference)
Power-down time-stamp (HT bit)
Battery low flag
Programmable alarm and interrupt function
Accurate programmable watchdog timer (from 62.5 ms to 128 s)
Software clock calibration
Operating temperature of -40 to 85 °C
Package options include an 8-lead SOIC or 18-lead embedded crystal SOIC

Applications
Timekeeping
Date and time stamping
Alarm and interrupt functions
Watchdog timers
Clock calibration
Battery backup applications