Low-Current, I²C, Serial Real-Time Clock

Analog Devices' DS1339A serial real-time clock (RTC) is a low-power clock/date device 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/date 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 DS1339A has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply, maintaining time, date, and alarm operation.