M41T81 Description
The M41T81 is a low-power serial RTC with a built-in 32.768 kHz oscillator (external crystal controlled). Eight bytes of the SRAM are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. An additional 12 bytes of SRAM provide status/control of alarm, watchdog and square wave functions.
M41T81 Key Features
- For all new designs use M41T81S
- Counters for tenths/hundredths of seconds
- 32 KHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high cry
- Serial interface supports I2C bus (400 kHz protocol)
- Ultra-low battery supply current of 0.6 ΜA (typ at 3 V)
- 2.0 to 5.5 V clock operating voltage
- Power-down time stamp (HT bit) allowing determination of time elapsed in battery backup
- Programmable alarm and interrupt function (valid even during battery backup mode)
- Accurate programmable watchdog timer (from 62.5 ms to 128 s)
- Software clock calibration to pensate crystal deviation due to temperature