General Description
The DS3231M is a low-cost, extremely accurate, I2C realtime 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 piecepart 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 AM/PM indicator. Two programmable time-ofday 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 RST pin is monitored as a pushbutton
input for generating a microprocessor reset. See the
Block Diagram for more details.

Applications
Power Meters
Industrial Applications

Benefits and 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