M41T01M6F Serial real-time clock (RTC) with built-in battery switchover circuit

The M41T01 is a low-power serial real-time clock (RTC). The built-in 32.768 kHz oscillator circuit works with an external crystal and does not need any load capacitors.

The M41T01 clock has a built-in power sense circuit which detects power failures and automatically switches to the battery supply during power failures. 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 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 M41T01 is supplied in an 8-lead plastic small outline package.