DS1307 Real-Time Clock (RTC) Module – SMD Layout (Without Battery)
Ensure your microcontrollers never lose track of time. The DS1307 Real-Time Clock (RTC) Module is a high-accuracy, full binary-coded decimal (BCD) clock-calendar breakout board designed to provide long-term, stable timekeeping. It automatically manages seconds, minutes, hours, day, date, month, and year metrics with built-in leap-year compensation.
Featuring a streamlined, low-profile Surface Mount Device (SMD) component layout, this module is highly resistant to physical vibrations and fits cleanly into space-constrained enclosures. Utilizing the standard I2C communication protocol, it easily interfaces with your master boards while drawing negligible backup current. It is the perfect choice for high-end data loggers, automated industrial schedules, smart utility meters, and DIY clock builds.
Key Features
Full Calendar & Clock Engine: Computes complete time parameters including seconds, minutes, hours, date, month, day of the week, and year with leap-year compensation valid up to the year 2100.
Low-Profile SMD Architecture: Assembled using modern surface-mount components (SMD) to keep the module slim, lightweight, and robust against mechanical vibration inside moving industrial systems.
Standard I2C Bus Interface: Communicates using a simple 2-wire I2C interface (SDA and SCL), allowing multiple I2C sensors to share the same hardware lines on your Arduino or Raspberry Pi.
Automatic Power-Fail Sensing: Features an onboard voltage-sensing circuit that instantly detects power drops and automatically switches the clock chip to backup battery power to prevent data loss.
Programmable Square-Wave Output: Equipped with an unpopulated pin hole capable of outputting a programmable square-wave signal ($1\text{ Hz}$, $4.096\text{ kHz}$, $8.192\text{ kHz}$, or $32.768\text{ kHz}$), ideal for driving external microchip hardware interrupts.
Technical Specifications
Feature | Specification |
Core RTC Chip | DS1307 (SMD Package) |
Communication Bus | I2C (Inter-Integrated Circuit) |
I2C Device Address | 0x68 (Fixed Hardware Address) |
Time Format Support | 24-Hour or 12-Hour (with AM/PM indicators) |
Onboard NVRAM | 56 Bytes of Non-Volatile, Battery-Backed Scratchpad RAM |
Operating Voltage | 4.5V to 5.5V DC Nominal |
Backup Battery Slot | Integrated CR2032 Battery Holder (Battery NOT Included) |
Board Dimensions | 28 mm x 27 mm x 10 mm |
Hardware Wiring & Pin Mapping
The DS1307 module breaks out 5 clearly labeled interface pins that easily map to any development board (Arduino, ESP32, STM32, Raspberry Pi):
VCC: Main Power Input Supply (+5V DC). Powers the module and I2C lines during normal operation.
GND: System Ground Reference.
SDA: Serial Data line for I2C data packet transfers.
SCL: Serial Clock line to synchronize I2C communication.
SQW: Square-Wave output pin (Optional use for hardware clock interrupts).
🔋 Note on Battery Power: This package does not include a CR2032 button cell battery. To ensure your project retains the correct time when disconnected from a USB cable or main power grid, please purchase a standard 3V CR2032 lithium coin battery separately and slide it into the onboard holder.
Common Applications
IoT Data Loggers: Essential for timestamping environmental parameters, GPS tracking coordinates, and sensor metrics saved to an SD card.
Smart Utility Meters: Tracks real-time electricity, water, or gas consumption logs against tariff schedules.
Biometric Attendance Systems: Powers the central time tracking loop for fingerprint and RFID check-in machinery.
Automated Appliance Timers: Automatically cycles streetlights, greenhouse watering pumps, or factory alarms based on specific hours of the day.
Package Includes:
1 x DS1307 Real-Time Clock (RTC) Module SMD Layout (Battery NOT included)