The DS3231SN#T&R with Real-time Clocks Clock/Calendar I2C, 2-Wire Serial is a low-power, temperature-compensated real-time clock (RTC) designed for use in devices requiring a timebase of reference. The device features an internally-generated clock signal, separate input and output supply pins that can be powered independently, and a programmable alarm that triggers on a time-of-day/date event or on an integer subsecond event. Other features include clock calendar where time is kept in a binary coded decimal (BCD) format, I2C bus, a power-on reset input (POR), automatic timekeeping adjustment for leap-year computation, and an analog temperature compensation applied to RTC timekeeping oscillator. It also has a power-savings feature that shuts off portion of the device when it is not in use. This is a SOIC-16_300mil RoHS package and the power consumption is 110uA ~ 170uA @ 3.63V ~ 5.5V. It is manufactured by Analog Devices.