The Renesas Electronics is real-time clock, low Cost and low power I2 C RTC/calendar with alarm function and dual IRQ pins.it is pin compatible and functionally equivalent to Maxim DS1337 and the oscillator uses an external, low-cost 32.768kHz crystal with 6pF load capacitance. The calendar is accurate through 2099 with
automatic leap year correction.

Dual interrupt for frequency output and alarm interrupt
Four selectable frequency output
Settable to the second, minute, hour, day of the week, and date
I2C interface
400kHz data transfer rate
Small package options day of the week, date, month, and year
Two alarms