Active production, I2C RTC for embedded timekeeping
The DS1337S+T&R is an active-production real-time clock from Analog Devices, carrying a Clock/Calendar type with I²C, 2-wire serial interface for direct connection to microcontrollers.
0.6µA timekeeping current and supply flexibility
The 0.6µA timekeeping current at 1.3V to 1.8V means a 40mAh coin cell sustains the RTC for over seven years in backup mode, assuming no other load on the cell. Timekeeping current is specified at the low end of the supply range; at 3.3V the actual draw is slightly higher but remains below 1µA typical, which is the figure to use for worst-case battery life calculations.
Timekeeping features and format support
The RTC supports both 12-hour and 24-hour time formats with HH:MM:SS resolution, and the date format is YY-MM-DD-dd, covering the full calendar including leap year compensation. Built-in features include an alarm, leap year tracking, and a square wave output — the alarm can be set to generate an interrupt on the SQW/INT pin, and the square wave output provides a programmable frequency reference without an external timer.