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DS1904
RTC iButton


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Status
Part Number Status
DS1904 Active: In Production. But some versions of the family are No Longer Available. See Ordering Information.

Data Sheet
FULL DATA SHEET (PDF, 284kB)
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Description
The DS1904 RTC iButton® is a rugged real-time clock module that can be accessed with minimal hardware. Data is transferred serially by the 1-Wire® protocol, which requires only a single data lead and a ground return. The DS1904 contains a unique 64-bit factory-lasered ROM and a real-time clock/calendar implemented as a binary counter. The durable MicroCan® package is highly resistant to environmental hazards such as dirt, moisture, and shock. Accessories permit the DS1904 to be mounted on almost any surface including printed circuit boards and plastic key fobs. The DS1904 adds functions such as calendar, time and date stamp, stopwatch, hour meter, interval timer, and logbook to any type of electronic device or embedded application that uses a microcontroller.

This product contains lithium-metal batteries. See applicable regulations for transport requirements for batteries in equipment.

Key Features
  • Real-time clock/calendar in binary format
  • Uses the same binary time/date representation as the DS1994 but with 1 second resolution
  • Clock accuracy is better than ± 2 minutes per month at +25°C
  • Operating temperature range from -40°C to +70°C
  • Over 10 years of operation
  • Unique, factory-lasered and tested 64-bit registration number (8-bit family code + 48-bit serial number + 8-bit CRC tester) assures absolute traceability because no two parts are alike
  • Multidrop controller for MicroLAN
  • Digital identification and information by momentary contact
  • Chip-based data carrier compactly stores information
  • Data can be accessed while affixed to object
  • Economically communicates to host with a single digital signal at 16.3kbits per second
  • Standard 16mm diameter and 1-Wire protocol ensure compatibility with iButton device family
  • Button shape is self-aligning with cup-shaped probes
  • Durable stainless steel case engraved with registration number withstands harsh environments
  • Easily affixed with self-stick adhesive backing, latched by its flange, or locked with a ring pressed onto its rim
  • Presence detector acknowledges when reader first applies voltage
  • Meets UL#913 (4th Edit.); Intrinsically Safe Apparatus, approved under Entity Concept for use in Class I, Division 1, Group A, B, C and D locations (application pending)
  • Underwriters Laboratories (UL®) Recognized

Key Specifications:  iButton Products
Part Number Overview Memory Type Memory Size Unique Ware Real Time Clock Smallest Available Pckg.
(mm2)
Price
max w/pins See Notes
DS1904 
RTC iButton
ROM Only 64 bits No Yes 301 $3.08 @1k
See All iButton Products (26)

Diagram

Application Notes
  • Application Note 27: Understanding and Using Cyclic Redundancy Checks with Maxim iButton Products - DS1904
  • Application Note 74: Reading and Writing 1-Wire® Devices Through Serial Interfaces - DS1904
  • Application Note 126: 1-Wire® Communication Through Software - DS1904
  • Application Note 148: Guidelines for Reliable Long Line 1-Wire® Networks - DS1904
  • Application Note 155: 1-Wire® Software Resource Guide Device Description - DS1904
  • Application Note 159: Software Methods to Achieve Robust 1-Wire® Communication in iButton® Applications - DS1904
  • Application Note 187: 1-Wire Search Algorithm - DS1904
  • Application Note 192: Using the DS2480B Serial 1-Wire Line Driver - DS1904
  • Application Note 244: Advanced 1-Wire Network Driver - DS1904
  • Application Note 1100: White Paper 5: Using 1-Wire APIs for Data Sheet Commands - DS1904
  • Application Note 3808: What Is an iButton? - DS1904
  • Application Note 4506: Alternatives to the DS1994L 4Kb Plus Time Memory iButton® - DS1904

    Reliability Reports
  • Request Reliability Report for:
  • Underwriters Laboratories (UL®) Recognized

    Software/Models
    none

    Ordering Information
    Notes:

    1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
    2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
    3. Part number suffixes: T or T&R = tape and reel;+ = RoHS/lead-free;# = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
    4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.


    Devices: 1-2 of 2

    DS1904 Free
    Sample
    Buy Status
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    Temp RoHS/Lead-Free?
    Materials Analysis
    DS1904L-F5+     N/A No Longer Available CAN-F5;2 pin;301 mm²
    Outline Drawing: 21-0266 (PDF)
    Land Pattern: Not Available
    Use pkgcode/variation: IB+5CW*
    0°C to +70°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1904L-F5#  
    Active CAN-F5;2 pin;301 mm²
    Outline Drawing: 21-0266 (PDF)
    Land Pattern: Not Available
    Use pkgcode/variation: IB#5CB*
    Special - See Data Sheet RoHS/Lead-Free: RoHS Qualified
    Materials Analysis

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    Document Ref.: 19-4864; 2009-09-29
    This page last modified: 2009-09-29


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