DS3231 High Precision Real Time Clock Module

DS3231 High Precision Real Time Clock Module is an extremely accurate I2C real-time clock (RTC) that features an integrated temperature-compensated crystal oscillator (TCXO) and crystal. This device maintains highly precise timekeeping by compensating for frequency changes caused by temperature fluctuations, which usually degrade the accuracy of standard RTC chips. Furthermore, the module includes a battery backup input, ensuring the device keeps continuous time even when you disconnect the main system power. Consequently, it serves as a superior upgrade for projects requiring long-term reliability without frequent time recalibration. Therefore, you should choose the DS3231 for any mission-critical application where maintaining a stable time base is essential.

Key Features:

• High Accuracy: The integrated TCXO ensures timekeeping accuracy remains within ±2 minutes per year from −40°C to +85°C.
• Integrated Temperature Sensor: The chip monitors ambient temperature and provides data via the I2C interface with an accuracy of ±3°C.
• Battery Backup: Supports a coin cell battery (typically CR2032) to maintain time and date settings during main power outages.
• Dual Alarm Clocks: Includes two programmable time-of-day alarms that can trigger an external interrupt signal.
• I2C Interface: Utilizes a simple two-wire interface for high-speed data transfer up to 400 kHz, making it compatible with most microcontrollers.

Technical Specifications:

• Operating Voltage: 3.3 V to 5.5 V
• Real-Time Clock: Tracks Seconds, Minutes, Hours, Day, Date, Month, and Year with Leap-Year Compensation until 2100.
• Clock Accuracy: ±2 ppm (parts per million)
• I2C Bus Speed: 400 kHz Maximum
• EEPROM Memory: Often paired with an AT24C32 chip on-module, providing 32 Kbits (4 KB) of non-volatile storage.
• Operating Temperature: −45°C to +85°C

Mechanical Specifications:

• Mounting Type: Through-hole pin headers (2.54 mm pitch)
• Battery Holder: Integrated clip-in holder for standard CR2032 lithium cells.
• PCB Material: High-quality FR-4 glass epoxy with tinned pads.

Dimensions:

• Module Length: ≈ 38 mm
• Module Width: ≈ 22 mm
• Module Height: ≈ 14 mm (including battery holder)

Pinout and Wiring:

• VCC: Connect to the positive power supply (3.3 V – 5.5 V).
• GND: Connect to the common system ground.
• SDA: Serial Data line for I2C communication; connect to the MCU SDA pin.
• SCL: Serial Clock line for I2C communication; connect to the MCU SCL pin.
• SQW: Square Wave/Interrupt output; provides a programmable frequency signal or alarm trigger.
• 32K: Outputs the stable 32.768 kHz signal directly from the TCXO.

Datasheet Reference:

• Download Maxim Integrated DS3231 Datasheet

Commonly Used in:

• Arduino Projects: Popular choice for time-stamping sensor data in DIY electronics.
• Data Loggers: Records the exact time of environmental or industrial events.
• Home Automation: Controls lighting and appliance schedules accurately.

Applications:

• Digital Clocks: Provides the time base for high-end wall clocks and desk timers.
• Power Meters: Tracks energy usage over specific time intervals in smart meters.
• Attendance Systems: Logs employee check-in and check-out times with high precision.

Equivalent Models:

• DS1307: A lower-cost alternative, however, it lacks the temperature compensation and precision of the DS3231.
• DS3232: Offers similar precision with additional internal SRAM for data storage.
• PCF8563: A low-power RTC from NXP, suitable for basic timekeeping but less accurate over varying temperatures.

Package Includes:

• 1 x DS3231 High Precision Real Time Clock Module (Battery not included)