The DS1306 serial alarm real-time clock (RTC) provides a full binary coded decimal (BCD) clock calendar that is accessed by a simple serial interface. The clock/calendar provides seconds, minutes, hours, day, date, month, and year information. The end of the month date is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with AM/PM indicator. In addition, 96 bytes of NV RAM are provided for data storage.

An interface logic-power supply input pin (VCCIF) allows the DS1306 to drive SDO and 32kHz pins to a level that is compatible with the interface logic. This allows an easy interface to 3V logic in mixed supply systems. The DS1306 offers dual-power supplies as well as a battery-input pin. The dual-power supplies support a programmable trickle charge circuit that allows a rechargeable energy source (such as a super cap or rechargeable battery) to be used for a backup supply. The VBAT pin allows the device to be backed up by a non-rechargeable battery. The DS1306 is fully operational from 2.0V to 5.5V.

Two programmable time-of-day alarms are provided by the DS1306. Each alarm can generate an interrupt on a programmable combination of seconds, minutes, hours, and day. "Don't care" states can be inserted into one or more fields if it is desired for them to be ignored for the alarm condition. A 1Hz and a 32kHz clock output are also available.

The DS1306 supports a direct interface to SPI™ serial data ports or standard 3-wire interface. An easy-to use address and data format is implemented in which data transfers can occur 1-byte at a time or in multiple-byte Burst Mode®.
DS1306:標準動作回路 DS1306:標準動作回路 拡大表示+


  • Completely Manages All Timekeeping Functions
    • Real-Time Clock (RTC) Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2100
    • 96-Byte, Battery-Backed NV RAM for Data Storage
    • Two Time-Of-Day Alarms, Programmable on Combination of Seconds, Minutes, Hours, and Day of the Week
    • 1Hz and 32.768kHz Clock Outputs
  • Standard Serial Port Interfaces with Most Microcontrollers
    • Supports Motorola SPI (Serial Peripheral Interface) Modes 1 and 3 or Standard 3-Wire Interface
    • Burst Mode for Reading/Writing Successive Addresses in Clock/RAM
  • Multiple Power Supply Pins Ease Adding Battery For Backup
    • Dual-Power Supply Pins for Primary and Backup Power Supplies
    • Optional Trickle Charge Output to Backup Supply
    • 2.0V to 5.5V Operation
  • Optional Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications
  • 20-Pin TSSOP Minimizes Required Space
  • Underwriters Laboratory (UL®) Recognized

スペックパラメータを参照する: Timekeeping & Real-Time Clocks (78)

Part NumberInterfaceVSUPPLY
Time Keeping Current
Memory TypeMemory Size
Time of Day AlarmsFunctionsPackage/PinsBudgetary
typSee Notes
$2.37 @1k



チュートリアル 5791 Tips for Writing Bulletproof Real-Time Clock Control Code
チュートリアル 5413 State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks
アプリケーションノート 4247 Oscillator Design Considerations for Low-Current Applications
アプリケーションノート 3816 Selecting a Backup Source for Real-Time Clocks
アプリケーションノート 3517 トリクルチャージャのリアルタイムクロックのスーパーキャパシタのバックアップ時間を推定する方法
アプリケーションノート 3510 DS1305 RTCと8051互換マイクロコントローラとのインタフェース接続
アプリケーションノート 2833 Interfacing an SPI RTC with a Motorola DSP
アプリケーションノート 2361 Interfacing an SPI-Interface RTC with a PIC Microcontroller
アプリケーションノート 701 Using the DS32kHz with Maxim Real-Time Clocks
アプリケーションノート 505 リチウムコインセルバッテリ:アプリケーション寿命の予測
アプリケーションノート 504 Design Considerations for Maxim Real-Time Clocks
アプリケーションノート 502 Interfacing SPI Real-Time Clocks (RTCs) with a Microcontroller
アプリケーションノート 82 Using the Dallas Tricklecharge Timekeeper
アプリケーションノート 58 Crystal Considerations with Maxim Real-Time Clocks (RTCs)


製品の信頼性レポート: DS1306.pdf 
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±5ppm, I2C Real-Time Clock with Integrated MEMS Oscillator

  • Highly Accurate RTC with Integrated MEMS Resonator Completely Manages All Timekeeping Functions
  • 64-Byte RAM for User Data Storage
  • Simple Serial Interface Connects to Most Microcontrollers