DS3231

The DS3231 is a low-cost, extremely accurate I² C real-time clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, and maintains accu-rate timekeeping when main power to the device is inter-rupted. The integration of the crystal resonator enhances the long-term accuracy of the device as well as reduces the piece-part count in a manufacturing line. The DS3231 is available in commercial and industrial temperature ranges, and is offered in a 16-pin, 300-mil SO package.

The DS3231 RTC maintains 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 an AM /PM indicator. Two programmable time-of-day alarms and a programmable square-wave output are provided. Address and data are transferred serially through an I²C bidirectional bus.

A precision temperature-compensated voltage refer-ence and comparator circuit monitors the status of V_CC to detect power failures, to provide a reset output, and to automatically switch to the backup supply when nec-essary. Additionally, the DS3231 RST  pin is monitored as a pushbutton input for generating a reset externally.