Adafruit DS3231 Precision RTC Breakout

The Adafruit DS3231 Precision RTC is a highly accurate I2C real-time clock breakout with an integrated temperature-compensated crystal oscillator (TCXO). Unlike standard RTCs that rely on an external 32 kHz crystal, the DS3231 houses the crystal internally alongside a temperature sensor that continuously compensates for frequency drift, delivering accuracy of ±2 ppm (about ±1 minute per year).

With a CR1220 coin cell on the back, the DS3231 maintains precise timekeeping for years even when main power is lost — ideal for data logging, clocks, and any project where reliable time is critical.

Key Features

• Integrated TCXO – On-chip crystal and temperature sensor for automatic drift compensation
• ±2 ppm Accuracy – Approximately ±1 minute per year, far superior to standard RTCs
• Battery Backup – CR1220 coin cell holder on board for uninterrupted timekeeping during power loss
• I2C Interface – Simple two-wire communication with standard I2C addressing
• Low Power – Minimal current draw in battery-backup mode
• Breadboard-Friendly – Compact breakout with included header strip

Also Available

• DS3231 Precision RTC – STEMMA QT version (solderless I2C connectors)
• DS1307 RTC Breakout (basic, lower cost)
• PCF8523 RTC Breakout (3.3V compatible)

Ideal For

• Precision data logging with accurate timestamps
• Clocks and timers requiring minimal drift
• IoT devices needing reliable timekeeping through power cycles
• Projects where an external crystal's temperature sensitivity is unacceptable

Package Contents

• 1× Adafruit DS3231 Precision RTC Breakout (fully assembled and tested)
• 1× Header strip