Microchip MCP7940NT-I/MS, Real Time Clock, 64B RAM Serial, 8-Pin MSOP

The Microchip Low power Real Time Clocks uses digital timing compensation for an accurate clock/calendar, a programmable output control for versatility, and a power sense circuit that automatically switches to the backup supply. Using a low cost 32.768 kHz crystal, it tracks time using several internal registers. For communication, it uses the I2C™ bus. The clock/calendar automatically adjusts for months with fewer than 31 days, including corrections for leap years.

Dual programmable alarms​
Versatile output pin​
Clock output with selectable frequency​
Alarm output​
General purpose output​
Time logged on switchover to and from battery backup​
64 bytes battery backed SRAM