Parallel-Interface Elapsed Time Counter

Subsecond Elapsed-Time Counter Offers 244µs Resolution

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The DS1318 parallel-interface elapsed time counter (ETC) is a 44-bit counter that maintains the amount of time that the device operates from main and/or backup power or during an external event. The internal frequency of the counter clock is 4.096kHz, which provides a 244µs resolution and a maximum count of over 136 years. A built-in power-sense circuit detects power failures, automatically switches to the backup supply, and controls the timer. If an external event timer is desired, the control input EXT can control the counter operation. An open-drain output provides an interrupt, and a square-wave output provides a programmable square wave. The DS1318 is accessed through a byte-wide parallel interface, and operates over the industrial temperature range.
DS1318: Typical Operating Circuit DS1318: Typical Operating Circuit Enlarge+

Key Features

  • Byte-Wide Parallel Interface
  • 44-Bit Binary Counter Provides Timer with 244µs Resolution
  • Automatic Power-Fail Detect and Switch Circuitry Selects Power Source from the Primary Power and the Battery, and Write Protects the Internal Registers
  • Internal Power-Fail Circuit Allows Timer to Provide Primary or Battery Operation Times
  • Timer can Alternately Provide an Event Timer of Either an Active-High or Active-Low Pulse
  • Interrupt Output Generated Periodically or When the Upper 32 Bits of the Counter Match an Alarm Register
  • Square-Wave Output with 16 Selectable Frequencies from 32.768kHz to 0.5Hz
  • +3.3V Operation
  • Industrial Temperature Range: -40°C to +85°C


  • Industrial Controls
  • Power Metering
  • Servers
Part NumberInterfaceVSUPPLY
Time Keeping Current
Memory TypeTime of Day AlarmsFunctionsPackage/PinsBudgetary
typSee Notes
DS1318 Bytewide3.375012.5None1Elapsed Time Counter
$1.89 @1k
See All Timekeeping & Real-Time Clocks (76)
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.

CAD Symbols and Footprints

  • DS1318E+
  • DS1318E+T&R
  • DS1318E/GG8
  • 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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