DS3231 Real Time Clock Module with AT24C32 EEPROM — I2C
The DS3231 is the most accurate low-cost RTC available for Arduino projects, with a temperature-compensated crystal oscillator (TCXO) that maintains time to within +/-2 minutes per year — far more accurate than the DS1307’s +/-20 minutes per year. The module also includes a 32K AT24C32 EEPROM for non-volatile data storage, a CR2032 coin cell holder for backup power, and a square-wave/interrupt output pin.
- DS3231 TCXO — +/-2 minutes per year accuracy (0.000038% error)
- AT24C32 EEPROM included — 32KB non-volatile data storage
- CR2032 backup battery holder — keeps time without main power
- I2C interface — RTC at 0x68, EEPROM at 0x57
- Square-wave output — 1Hz, 1kHz, 4kHz, or 8kHz selectable
- Alarm outputs — two configurable alarms with interrupt pin
| Specification | Value |
|---|---|
| RTC IC | DS3231SN |
| Accuracy | +/-2 minutes per year (TCXO) |
| EEPROM | AT24C32 — 32KB |
| Interface | I2C (RTC 0x68, EEPROM 0x57) |
| Backup battery | CR2032 (not included) |
| Supply voltage | 3.3V – 5.5V |
How accurate is the DS3231 compared to the DS1307?
The DS3231 uses a temperature-compensated crystal that corrects for frequency drift as temperature changes. Over a year, it loses or gains under 2 minutes. The DS1307 uses a simpler crystal that drifts up to 20 minutes per year without software correction. For timestamped data logging that needs to remain accurate over months without resynchronisation, the DS3231 is the correct choice.
Best for
Arduino data loggers with accurate timestamps, alarm clocks, calendar displays, event schedulers, long-running battery-powered sensors needing accurate time, and any project where the DS1307 drifts too much.
Why Kunkune
Shipped from UK stock. 60-day returns, no minimum order. Fast Royal Mail delivery.
Buying in bulk? For orders of 10+ units, contact us for trade pricing.
