Note
The battery is not included.
Features
Real-Time Clock (RTC) counts seconds, minutes, hours, date of the month, month, day of the week, and year with Leap-Year compensation valid up to 2100
56-Byte, Battery-Backed, Nonvolatile (NV)RAM for data storage
I2C serial interface
5V DC supply
Programmable Square-Wave output signal
Automatic Power-Fail detect and switch circuitry
Consumes less than 500nA in Battery-Backup Mode with Oscillator Running