The M41T00 is a low power serial real-time clock with a built-in 32.768 kHz oscillator (external crystal controlled). Eight bytes of the RAM are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. Addresses and data are transferred serially via a two-line bidirectional bus. The built-in address register is incremented automatically after each WRITE or READ data byte.
The M41T00 clock has a built-in power sense circuit which detects power failures and automatically switches to the battery supply during power failures. The energy needed to sustain the RAM and clock operations can be supplied from a small lithium coin cell.
Typical data retention time is in excess of 5 years with a 50 mA/h 3 V lithium cell.
The M41T00 is supplied in an 8-lead plastic small outline package.
- For new designs use M41T00S
- Counters for seconds, minutes, hours, day, month, years, and century
- 32 kHz crystal oscillator integrating load capacitance (12.5 pF) providing exceptional oscillator stability and high crystal series resistance operation
- Serial interface supports I2C bus (100 kHz protocol)
- Ultra low battery supply current of 0.8 μA (typ at 3 V)
- 2.0 to 5.5 V clock operating voltage
- Automatic switchover and deselect circuitry (for 3 V application select M41T00S datasheet)
- Software clock calibration to compensate crystal deviation due to temperature
- Automatic leap year compensation
- Operating temperature of -40 to 85 °C
(**) The Material Declaration forms available on st.com may be generic documents based on the most commonly used package within a package family. For this reason, they may not be 100% accurate for a specific device. Please contact our sales support for information on specific devices.