DS1994

iButton 4Kb Memory Plus Time


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Description

The iButton® 4Kb Memory Plus Time (DS1994) is a rugged read/write data carrier that acts as a localized database, easily accessible with minimal hardware. The nonvolatile memory and optional timekeeping capability offer a simple solution to storing and retrieving vital information pertaining to the object to which the iButton device is attached. Data is transferred serially through the 1-Wire® protocol that requires only a single data lead and a ground return.

The scratchpad is an additional page that acts as a buffer when writing to memory. Data is first written to the scratchpad where it can be read back. After the data has been verified, a copy scratchpad command transfers the data to memory. This process ensures data integrity when modifying the memory. A 48-bit serial number is factory lasered into each DS1994 to provide a guaranteed unique identity that allows for absolute traceability. The durable MicroCan package is highly resistant to environmental hazards such as dirt, moisture, and shock. Its compact, coin-shaped profile is self-aligning with mating receptacles, allowing the DS1994 to be easily used by human operators. Accessories permit the DS1994 to be mounted on almost any surface including plastic key fobs, photo-ID badges, and PC boards.

The DS1994 also includes time-keeping functions, a real-time clock/calendar, interval timer, cycle counter, and programmable interrupts, in addition to the nonvolatile memory. The internal clock can be programmed to deny memory access based on absolute time/date, total elapsed time, or the number of accesses. These features allow the DS1994 to be used to create a stopwatch, alarm clock, time and date stamp, logbook, hour meter, calendar, system power cycle timer, interval timer, and event scheduler.
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Key Features

  • 4096 bits of Read/Write Nonvolatile Memory
  • 256-bit Scratchpad Ensures Integrity of Data Transfer
  • Memory Partitioned into 256-bit Pages for Packetizing Data
  • Data Integrity Assured with Strict Read/Write Protocols
  • Contains Real-Time Clock/Calendar in Binary Format
  • Interval Timer Can Automatically Accumulate Time When Power is Applied
  • Programmable Cycle Counter can Accumulate the Number of System Power-On/Off Cycles
  • Programmable Alarms Can Be Set to Generate Interrupts for Interval Timer, Real-Time Clock, and/or Cycle Counter
  • Write-Protect Feature Provides Tamperproof Time Data
  • Programmable Expiration Date That Limits Access to SRAM and Timekeeping
  • Clock Accuracy is Better Than ±2 Minutes/Month at 25°C
  • Operating Temperature Range from -40°C to +70°C
  • Over 10 Years of Data Retention

Technical Documents

App Note 4506 Alternatives to the DS1994L 4Kb Plus Time Memory iButton®
Reference Schematic 244 Advanced 1-Wire Network Driver
App Note 155 1-Wire Software Resource Guide Device Description

Quality and Environmental Data

Product Reliability Reports: DS1994.pdf 
Lead-Free Package Tin (Sn) Whisker Reports
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.

Quality Management System >
Environmental Management System >

 
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Related Resources

Type ID Title
Reference Circuit244Advanced 1-Wire Network Driver

Belle Isle 2020
05/29/2020 - 05/31/2020, Detroit, MI
2020 Detroit Grand Prix - Chevrolet Detroit Grand Prix presented by Lear Fast Facts The Chevrolet Detroit Grand Prix presented by Lear was hosted on Belle Isle, May 29 - 30 2020. The event featured the cars of the NTT IndyCar Series, the IMSA WeatherTech SportsCar Championship and the Trans Am Series presented by Pirelli. The weekend is collectively referred to as the Chevrolet Detroit Grand Prix presented by Lear and it once again featured the Chevrolet Dual in Detroit IndyCar doubleheader.

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