The DS3231 is a low-cost, extremely accurate I2C 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 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 VCC to detect power failures, to provide a reset output, and to automatically switch to the backup supply when nec- essary. Additionally, the RST pin is monitored as a pushbutton input for generating a µP reset. Applications Servers Utility Power Meters Telematics GPS
The DS3231 provides a highly accurate real‑time clock (RTC) with an integrated temperature‑compensated crystal oscillator (TCXO). It maintains seconds, minutes, hours, day, date, month and year, automatically adjusting for leap years and month length. The device operates over a wide temperature range and includes two programmable time‑of‑day alarms and a programmable square‑wave output.
The chip is supplied in a 16‑pin SO package, supports 3.3 V operation, and includes a push‑button reset pin, a low‑power standby mode, and a voltage‑reference/comparator that switches to backup battery power when VCC fails. Detailed electrical characteristics, pin functions, and timing diagrams are provided for designers.
| Accuracy (Commercial Temp Range) | ±2 ppm (0 °C to +40 °C) |
|---|---|
| Accuracy (Industrial Temp Range) | ±3.5 ppm (‑40 °C to +85 °C) |
| Operating Temperature (Commercial) | 0 °C to +70 °C |
| Active Supply Current (VCC = 5.5 V) | 300 µA |
| Standby Supply Current (VCC = 5.5 V) | 170 µA |
| Number of Alarms | 2 programmable time‑of‑day alarms |
It provides two programmable time‑of‑day alarms.
The accuracy is ±3.5 ppm from –40 °C to +85 °C.