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Small green circuit board with silver battery holder and integrated chip

Adafruit

Adafruit DS1307 Real Time Clock Breakout Board engineering development tool

SKU CH-ZEK9-2AMT6

Battery-backed DS1307 real-time clock keeps time during power loss for Arduino or Raspberry Pi datalogging projects

  • Product typeEngineering Development Tools
  • Keeps accurate time during power loss with battery-backed DS1307 RTC
  • Integrates easily with Arduino via Adafruit library or Raspberry Pi
  • Compact 25.8 mm × 21.7 mm board fits tight enclosures
  • Supports datalogging, clock-building, time-stamping, timers and alarms
  • Communicates over I2C at address 0x68 with 5 V supply

Battery-Backed Timekeeping

The Adafruit DS1307 breakout board adds a real-time clock to microcontroller projects. It tracks seconds, minutes, hours, days, months and years even when main power is removed. A coin cell maintains the register contents during reprogramming or power loss. The module communicates over I2C using the 7-bit address 0x68.

Long-Term Drift Characteristics

The DS1307 is a low-cost device rather than a high-precision oscillator. Typical deviation reaches roughly two seconds per day under continuous operation. Error accumulates linearly, so periodic correction in software is advisable for datalogging or scheduling tasks that demand tighter accuracy over weeks or months.

Upgrade Path and Constraints

This board suits hobbyists adding timestamps to Arduino or Raspberry Pi builds where 5 V supply is available. It does not suit designs that require sub-second accuracy, temperature-compensated crystals or 3.3 V-only operation without level shifting. Projects needing calendar alarms beyond simple square-wave output will need a different RTC chip.

How it compares

Measured against everything we stock in Engineering Workstations & Dev Kits, at today’s prices. Recalculated every night.

Price $13.99
Pricier than about 60% of the 170 comparable items (median $11.49).

Specifications

Product
Product typeEngineering Development Tools

Questions about this item

How much current does the DS1307 breakout draw when running continuously?

The DS1307 chip itself consumes very low microamp-level current in timekeeping mode; the breakout board adds only the pull-up resistors and coin-cell holder, so total draw stays negligible for battery-backed operation.

What microcontroller voltage and library are needed to use this RTC board?

The board requires 5 V power but works with 3.3 V logic; it communicates over I2C at address 0x68 and is supported by the Adafruit RTC library for Arduino or Raspberry Pi.

Will the DS1307 module share the I2C bus cleanly with older 5 V sensors I already have?

Yes, the board uses the standard I2C 7-bit address 0x68 and 5 V-tolerant pins, so it can sit on the same bus as legacy 5 V devices without level-shifting issues.

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