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3 Volt/5 Volt Serialized Real-Time Clock with NV RAM Control

Product Details

Key Features

Simplified Block Diagram

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Key Features

Incorporates industry standard DS1287 PC clock plus enhanced features:
  • +3 or +5V operation
  • 64-bit Silicon serial number
  • 64-bit customer specific ROM or additional serial number available
  • Power control circuitry supports system power on from date/time alarm or key closure
  • Automatic battery backup and write protection to external SRAM
  • Crystal select bit allows RTC to operate with
  • 6pF or 12.5pF crystal
  • 114 bytes user NV RAM
  • Auxiliary battery input
  • RAM clear input
  • Century register
  • 32kHz output for power management
  • 32-bit VCC powered elapsed time counter
  • 32-bit VBAT powered elapsed time counter
  • 16-bit power cycle counter
  • Compatible with existing BIOS for original DS1287 functions
  • Available as IC (DS1688) or stand-alone module with embedded battery and crystal (DS1691)
  • Timekeeping algorithm includes leap year compensation valid up to 2100

Applications/Uses

Description

The DS1688/DS1691 is a real-time clock (RTC) designed as a successor to the industry standard DS1285, DS1385, DS1485, and DS1585 PC real time clocks. This device provides the industry standard DS1285 clock function with the new feature of either +3.0 or +5.0V operation and automatic backup and write protection to an external SRAM. The DS1688 also incorporates a number of enhanced features including a silicon serial number, power on/off control circuitry, 114 bytes of user NV SRAM, power on elapsed timer, and power cycle counter.

Simplified Block Diagram

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .