Industry’s smallest I²C RTC with two time-of-day alarms

The DS1337 serial real-time clock is a low-power clock/calendar with two programmable time-of-day alarms and a programmable square-wave output. Address and data are transferred serially through an I²C bus. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator.

The device is fully accessible through the serial interface while VCC is between 1.8V and 5.5V. I²C operation is not guaranteed below 1.8V. Timekeeping operation is maintained with VCC as low as 1.3V.

The DS1341 and DS1342 are pin compatible devices that allow use of crystals with an equivalent series resistance (ESR) up to 100kΩ.