The DS1307 is a proven RTC from Maxim/Dallas, offering programmable clock and calendar functionality with automatic month-end and leap-year correction through 2100. It communicates via a 2-wire I²C interface (SDA and SCL), handles time in BCD format, and features a programmable square‑wave output.
Crucially, the DS1307 integrates a power-fail detect circuit and automatically switches to its battery input when primary power fails — it requires less than 500 nA in backup mode, ensuring accurate timekeeping over years.
🛠 Technical Details
| Feature | Specification |
|---|---|
| Timekeeping | Seconds, Min, Hours, Day, Date, Month, Year, leap-year up to 2100 |
| RAM | 56 bytes battery-backed non-volatile SRAM |
| Interface | I²C two-wire serial (SDA/SCL) |
| Square‑wave Output | 1 Hz, 4 kHz, 8 kHz, 32 kHz (programmable) |
| Supply Voltage Range | 4.5V – 5.5V nominal; VBAT backup typically 3V |
| Backup Current | < 500 nA with oscillator running |
| Crystal | External 32.768 kHz required on X1 & X2 |
| Temperature Range | 0°C to +70°C (commercial), –40°C to +85°C (industrial variant) |
| Package | 8‑pin PDIP or SOIC (UL recognized) |
💡 Use Cases & Applications
-
⏱ Standalone Real-Time Clocks
Keep accurate time across power cycles in control panels, data loggers, and instrumentation. -
📅 Embedded Calendar and Time Stamps
Use in systems that need to record time-based logs, automation schedules, or event tracking. -
💾 Non‑volatile Data Storage
Leverage the 56 B SRAM for user-specific small data storage that persists during power loss. -
🌐 Arduino / Microcontroller Projects
Popular in hobbyist and IoT builds—via I²C, connects easily to Arduino, PIC, AVR or ARM MCU platforms for tasks like alarm clocks or time-based relay control -
📉 Low‑Power Battery Applications
Ideal for wearables or battery-powered clocks where long-term timekeeping and minimal backup drain are required.
🛠️ Pair With
-
🔋 Use with stable Power Supply Modules
-
🧩 Interface using Electronic Components like pull-up resistors, coin cell holders, crystals, and backup batteries
-
🛠 Ideal to set up using Tools & Accessories such as I²C tools, breakout boards, or breadboards
🎥 YouTube Tutorial
📺 DS1307 RTC module Arduino tutorial.
⚠️ Precautions & Tips
-
Always install a 32.768 kHz crystal with correct 12.5 pF load capacitance to maintain accuracy
-
Add a 0.1 µF bypass capacitor between VCC and GND to suppress SDA/SCL noise
-
Tie unused address registers high or low to prevent undefined counts or writes
-
Use a CR2032 lithium cell on VBAT to maintain time for years during power loss
🏁 Summary & Call‑to‑Action
The DS1307 RTC IC is a reliable, low-power solution for accurate time and date tracking, backed by battery for uninterrupted operation. Its built-in calendar logic, NV SRAM, and simple I²C communication make it an excellent choice for automation, logging, and embedded timing applications.
🛒 Available now at Electroway — your go-to for RTCs and real-time embedded components.
Reviews
There are no reviews yet.