DS1308

Low-Current I²C RTC with 56-Byte NV RAM

Compatible with Any 32.768kHz Crystal


Please check latest availability status for a specific part variant.

Description

The DS1308 serial real-time clock (RTC) is a low-power, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV RAM. Address and data are transferred serially through an I²C 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 an AM/PM indicator. The DS1308 has a built-in power-sense circuit that detects power failures and automatically switches to the backup supply, maintaining time and date operation.
DS1308: Typical Operating Circuit DS1308: Typical Operating Circuit Enlarge+

Key Features

  • Compatible with Crystal ESR Up to 100kΩ Allows a Crystal to be Optimized for Cost and Space
  • Low-Power Operation Extends Battery Backup Run Time
    • Low Timekeeping Current of 250nA (typ)
    • Automatic Power-Fail Detect and Switch Circuitry
  • Completely Manages All Timekeeping Functions
    • Real-Time Clock Counts Seconds, Minutes, Hours, Date of the Month, Month, Day of the Week, and Year with Leap-Year Compensation Valid Up to 2400
    • External Clock Source for Synchronization Clock Reference (e.g., 32kHz, 50Hz/60Hz Powerline, GPS 1PPS)
    • 56-Byte, Battery-Backed, General-Purpose RAM with Unlimited Writes
    • Programmable Square-Wave Output Signal
  • Simple Serial Port Interfaces with Most Microcontrollers
    • I2C Serial Interface
  • Industrial Temperature Range: -40°C to +85°C Supports Operation in a Wide Range of Applications
  • Underwriters Laboratories (UL®) Recognized

Applications/Uses

  • Consumer Electronics (Set-Top Box, Digital Recording, Network Appliance)
  • Handhelds (GPS, POS Terminal)
  • Medical (Glucometer, Medicine Dispenser)
  • Office Equipment (Fax/Printer, Copier)
  • Other (Utility Meter, Vending Machine, Thermostat, Modem)
  • Telecommunications (Router, Switcher, Server)
Part NumberInterfaceVSUPPLY
(V)
Time Keeping Current
(nA)
CL
(pF)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsFunctionsPackage/PinsBudgetary
Price
typSee Notes
DS1308 I2C
1.8
3
3.3
2506NV SRAM560RTC
µMAX/8
$1.56 @1k
See All Timekeeping & Real-Time Clocks (75)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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