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This real-time clock module (RTC) uses the DS3232 chip that integrates a crystal resonator and a temperature compensator, which improves the long-term accuracy of the module. In the range of -40°C to +85°C, the accuracy of DS3231 remains at ±3.5ppm (±0.3024 seconds/day).

The DS3232 integrates 236Byte SRAM storage that can store data with extremely low power consumption, and it also can be used in scenarios such as low power consumption collection of the Internet of Things.

The device incorporates a battery input and maintains high precision timing when the main power to the device is interrupted. The RTC provides information of seconds, minutes, hours, week, day, month, and year, and it can automatically adjust the date at the end of the month, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. Two programmable time-of-day alarms and a programmable square-wave output are provided. In addition, the RST pin can be used as a push-button input for microprocessor reset.

Note: Due to the latest air cargo regulations, the transport audit of special items such as batteries, magnets, and liquids will become very strict, so the RTC module does not come with batteries anymore, please purchase them locally. The button cell model that goes with the module is CR1220.

Connection Diagram

Board Overview

DS323X Selection Guide

Product Name
Fermion: DS3231M MEMS
 Precise RTC  Module
Fermion: DS3231 
Precision RTC Module
Fermion: DS3232
 Precision RTC Module
SKU DFR0641 DFR0819 DFR0821
Storage None None 236Byte
Integrated Resonator MEMS XTAL XTAL
Timing Current 2000nA 840nA 1500nA
Timing Precision ±5ppm (±0.432s/d) ±3.5ppm (±0.3024s/d) ±3.5ppm (±0.3024s/d)
Operating Voltage 3.3V-5.5V 3.3V-5.5V 3.3V-5.5V
Operating Temperature -45°C ~ 85°C -40°C ~ 85°C -40°C ~ 85°C
Introduction Integrated MEMS resonatr, reducing the risk of mechanical failure, suitable for use in strong and frequent vibration. A RTC module with integrated crystal resonator, featuring a higher precision and a lower  power consumption, suitable for use in the occasion in demand of high precision and low power. A RTC module with integrated crystal resonator, equipped with 236Byte SRAM storage inside, enabling it to store data at an extremely low power consumption, suitable for low-power loT applications requiring real-time clock.


  • Internal integrated crystal resonator, small deviation
  • Internal integrated temperature compensator, small temperature drift
  • Complete clock calendar function
  • Two programmable Time-of-Day alarms
  • 236Byte SRAM integrated internally

  • Applications
  • Event reminder
  • MCU external wakeup source
  • Clock and alarm output
  • IoT data collection and storage

  • Specification
  • Power Supply Voltage: 3.3V-5.5V
  • I2C Address: 0x68
  • SRAM: 236 Byte (0x14~0x1F)
  • Timing Range: 1970 ~ 2100
  • Working Temperature: -40°C ~ +85°C
  • Timing Accuracy: ±3.5ppm (±0.3024 sec/day)
  • Product Size: 22.5*21mm / 0.89*0.83 inch

  • Documents
  • Product wiki

  • Shipping List
  • Fermion: DS3232 Precise RTC (Breakout) x1
  • 2.54-7P Black Single Row Connector x1
  • The Fermion: DS3232 Precise RTC (Breakout) appears in the following collections:

    SKU DF-DFR0821