Extremely Accurate l2C-lntegrated
RTC/TCXO/Crystal
General Description
The DS3231 is a low-cost extremely accurate ,2C realtime clock (RTC) with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, and maintains accurate timekeeping when main power to the device is interrupted. 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 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/PW 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 reference and comparator circuit monitors the status of Vcc to detect power failures, to provide a reset output, and to automatically switch to the backup supply when necessary. Additionally, the RST pin is monitored as a pushbutton input for generating a uP reset.

Features
♦ Accuracy ±2ppm from 0°C to +40°C
♦ Accuracy ±3.5ppm from -40°C to +85°C
♦ Battery Backup Input for Continuous Timekeeping
♦ Operating Temperature Ranges
Commercial: 0°C to +70°C Industrial: -40°C to +85°C
♦ Low-Power Consumption
♦ Real-Time Clock Counts Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap Year Compensation Valid Up to 2100
♦ TWoTime-of-Day Alarms
♦ Programmable Square-Wave Output
♦ Fast (400kHz) l2C Interface
♦ 3.3V Operation
♦ Digital Temp Sensor Output: ±3°C Accuracy
♦ Register for Aging Trim
♦ RST Output/Pushbutton Reset Debounce Input
♦ Underwriters Laboratories (UL®) Recognized