The DS3231 is a very accurate real-time clock (RTC) that combines an integrated crystal, a temperature sensor and an I2C interface. Accuracy stays within ±2 ppm over the 0–40 °C temperature range, which means at most one minute of deviation per year. Unlike traditional RTC chips that use an external 32 kHz crystal and suffer from temperature-induced drift, this chip compensates for changes using the internal sensor. This provides very stable and reliable timekeeping in a small, low-power package.

The breakout board is made for ease of use. It is development-board friendly and equipped with SparkFun Qwiic / STEMMA QT-compatible connectors. This allows the board to be connected directly to a microcontroller without soldering — a cable is all you need. The RTC works with both 3.3 V (e.g. Feather, Raspberry Pi) and 5 V (e.g. Arduino) logic. It is easy to use with Adafruit's CircuitPython/Python and Arduino libraries.

A CR1220 battery can be attached to the back of the board to maintain time for several years when main power is lost. The board ships assembled and tested. Battery not included.

Features:

• Very accurate real-time clock (RTC)
• Accuracy: ±2 ppm over 0–40 °C (±1 min/year)
• Integrated 32 kHz crystal and temperature sensor
• I2C interface, address 0x68
• STEMMA QT / Qwiic-compatible connectors
• Works with 3.3 V and 5 V logic
• Breadboard-friendly design
• 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