±5ppm, I2C Real-Time Clock

Industry's First Temperature-Compensated RTC with Internal MEMS Resonator Reduces Crystal Mechanical Failure Susceptibility


The DS3231M is a low-cost, extremely accurate, I2C real-time clock (RTC). The device incorporates a battery input and maintains accurate timekeeping when main power to the device is interrupted. The integration of the microelectromechanical systems (MEMS) resonator enhances the long-term accuracy of the device and reduces the piece-part count in a manufacturing line. The DS3231M is available in the same footprint as the popular DS3231 RTC.

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 active-low AM/PM indicator. Two programmable time-of-day alarms and a 1Hz 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 active-low RST pin is monitored as a pushbutton input for generating a microprocessor reset. See the Block Diagram in the full data sheet for more details.
DS3231M: Typical Operating Circuit DS3231M: Typical Operating Circuit Enlarge+

Key Features

  • Highly Accurate RTC With Integrated MEMS Resonator Completely Manages All Timekeeping Functions
    • Complete Clock Calendar Functionality Including Seconds, Minutes, Hours, Day, Date, Month, and Year, with Leap-Year Compensation Up to Year 2100
    • Timekeeping Accuracy ±5ppm (±0.432 Second/Day) from -45°C to +85°C
    • Footprint and Functionally Compatible to DS3231
    • Two Time-of-Day Alarms
    • 1Hz and 32.768kHz Outputs
    • Reset Output and Pushbutton Input with Debounce
    • Digital Temp Sensor with ±3°C Accuracy
    • +2.3V to +5.5V Supply Voltage
  • Simple Serial Interface Connects to Most Microcontrollers
    • Fast (400kHz) I2C Interface
  • Battery-Backup Input for Continuous Timekeeping
    • Low Power Operation Extends Battery-Backup Run Time
  • Operating Temperature Range: (-40°C to +85°C)
  • 8-Pin or 16-Pin SO Packages
  • Underwriters Laboratories® (UL) Recognized


  • Industrial Applications
  • Power Meters
Part Number Interface VSUPPLY
Time Keeping Current
Memory Type Time of Day Alarms Integrated Resonator Functions Package/Pins Budgetary
typ See Notes
DS3231M  I2C 2.3 to 5.5 2000 None 2 MEMs RTC
$3.54 @1k
See All Timekeeping & Real-Time Clocks (76)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

DS3231MPMB1: DS3231MPMB1 Peripheral Module
DS3231MZEVKIT: Evaluation Kits for the DS3231M or DS3232M
DS3232MEVKIT: Evaluation Kits for the DS3231M or DS3232M

Tools & Models

DS3231M IBIS Model

DS323X_DS1338_DS1341_DS1683 EVKIT GUI setup V1.0

Related Resources