Adafruit DS3231 Precision RTC Breakout

The DS3231 is an extremely accurate real-time clock (RTC) featuring an integrated crystal, temperature sensor, and I2C interface. Accuracy is maintained at ±2 ppm from 0–40 °C, which corresponds to a drift of less than one minute per year. Unlike standard RTCs that rely on external 32 kHz crystals and suffer from temperature-related drift, this device compensates for variations using the internal sensor. The result is stable, reliable timekeeping in a compact, low-power package.

The breakout board is designed for ease of use. It is breadboard-friendly and equipped with SparkFun Qwiic-compatible STEMMA QT connectors, enabling solder-free connection with just a cable. Operation is supported with both 3.3 V logic (e.g., Feather, Raspberry Pi) and 5 V logic (e.g., Arduino). Adafruit CircuitPython/Python and Arduino libraries are available for quick integration.

A CR1220 coin cell can be attached on the back to maintain timekeeping for years even when main power is lost. The breakout comes fully assembled and tested, with a small piece of header included. A coin cell is not included.

Features:

• Extremely accurate real-time clock (RTC)
• Accuracy: ±2 ppm at 0–40 °C (±1 min/year)
• Integrated 32 kHz crystal and temperature sensor
• I2C interface, address 0x68
• STEMMA QT / Qwiic compatible connectors
• Compatible with 3.3 V and 5 V logic
• Breadboard-friendly form factor
• Battery backup with CR1220 coin cell (not included)
• Size: 25.4 × 25.4 mm (1" × 1")

Package Includes:

• 1 × DS3231 RTC Breakout (assembled and tested)
• Pin header

Links:

• Product page