DS1302 Real-Time Clock (RTC) Module – SMD Layout (Without Battery)
Keep track of the exact time, date, and year in your embedded electronics, even when your main microcontroller is completely powered off. The DS1302 Real-Time Clock (RTC) Module is a highly efficient, timekeeping breakout board engineered to maintain year, month, date, day, hour, minute, and second metrics with absolute accuracy.
This module features a low-profile, vibration-resistant Surface Mount Device (SMD) layout that minimizes footprint and handles mechanical stress exceptionally well. Featuring a dedicated CR2032 backup battery holder and trickle-charge capabilities, it is the premier cost-effective choice for data loggers, automated attendance systems, smart digital clocks, and industrial automation control schedules.
Key Features
Complete Timekeeping Tracking: Computes seconds, minutes, hours, date of the month, month, day of the week, and year with leap-year compensation valid up to the year 2100.
Low-Profile SMD Architecture: Built using high-precision surface-mount components (SMD) to keep the module slim, lightweight, and robust against structural vibration inside moving enclosures.
Simple 3-Wire Serial Interface: Communicates with your microcontroller via a straightforward synchronous serial bus (CLK, I/O, CE), using only 3 digital I/O pins instead of memory-heavy I2C/SPI overhead.
Onboard Trickle-Charge Facility: Features internal dual power supply routing. When main power is available, it can safely trickle-charge a rechargeable backup battery or supercapacitor automatically.
Vibration-Stable Tuning: Equipped with an onboard high-stability 32.768 kHz crystal oscillator, ensuring consistent time ticking across variable ambient environments.
Technical Specifications
Feature | Specification |
Core RTC Chip | DS1302 (SMD Package) |
Time Format Support | 24-Hour or 12-Hour (with AM/PM indicators) |
RAM Space Allocation | 31 Bytes of Non-Volatile Scratchpad RAM |
Interface Type | 3-Wire Serial Interface (CE, I/O, SCLK) |
Operating Voltage | 2.0V to 5.5V DC |
Ultra-Low Active Power | Consumes less than 300 nA at 2.0V in battery backup state |
Backup Battery Slot | Integrated CR2032 Battery Holder (Battery NOT Included) |
Board Dimensions | 44 mm x 23 mm x 12 mm |
Hardware Wiring & Pin Mapping
The DS1302 module breaks out 5 clearly labeled interface pins that easily map to any development board (Arduino, ESP32, STM32, Raspberry Pi):
VCC2 / VCC: Main Power Input Supply (+5V or +3.3V DC). Powers the module during normal operation.
GND: System Ground Reference.
CLK / SCLK: Serial Clock Pin. Synchronizes data transfer across the 3-wire bus.
I/O / DAT: Bi-directional Data Pin. Transfers time and calendar bits back and forth to the microchip.
CE / RST: Chip Enable / Reset Pin. Must be driven HIGH to initiate data communication strings with the module.
🔋 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
SD Card Data Loggers: Essential for stamping exact date and time logs onto telemetry data collected from weather sensors or GPS trackers.
Smart Digital Clocks & Alarms: Acts as the stable time base engine for large 7-segment displays, dot-matrix arrays, or LCD alarm displays.
Automated Attendance Systems: Tracks school or office check-in stamps accurately on RFID and biometric reading rigs.
Industrial Timer Switches: Automates streetlights, agricultural watering pumps, or factory machinery cycles based on scheduling parameters.
Package Includes:
1 x DS1302 Real-Time Clock (RTC) Module SMD Layout (Battery NOT included)