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Maxim > Products > Real-Time Clocks 
DS1747, DS1747P
Y2K-Compliant, Nonvolatile Timekeeping RAMs


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Data Sheet
FULL DATA SHEET (PDF, 392kB)
Download this datasheet in PDF formatDownload   Send this datasheet to any email addressE-Mail

Description
The DS1747 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 512k x 8 nonvolatile static RAM. User access to all registers within the DS1747 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour binary-coded decimal (BCD) format. Corrections for the date of each month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data that can occur during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1747 also contains its own power-fail circuitry that deselects the device when the VCC supply is in an out-of-tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.

Key Features
  • Integrated NV SRAM, Real-Time Clock (RTC), Crystal, Power-Fail Control Circuit, and Lithium Energy Source
  • Clock Registers are Accessed Identically to the Static RAM. These Registers are Resident in the Eight Top RAM Locations
  • Century Byte Register (Y2K Compliant)
  • Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power
  • BCD-Coded Century, Year, Month, Date, Day, Hours, Minutes, and Seconds with Automatic Leap Year Compensation Valid Up to the Year 2100
  • Battery Voltage-Level Indicator Flag
  • Power-Fail Write Protection Allows for ±10% VCC Power-Supply Tolerance
  • Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is Applied for the First Time
  • DIP Module Only:
    • Standard JEDEC Byte-Wide 512k x 8 Static RAM Pinout
  • PowerCap® Module Board Only:
    • Surface-Mountable Package for Direct Connection to PowerCap Containing Battery and Crystal
    • Replaceable Battery (PowerCap)
    • Power-On Reset Output
    • Pin-for-Pin Compatible with Other Densities of DS174xP Timekeeping RAM
  • Also Available in Industrial Temperature Range: -40°C to +85°C
  • Underwriters Laboratories (UL®) Recognized

Key Specifications:   Timekeeping & Real-Time Clocks
Part Number Time Format (hh = sec/100) Date Format Interface Supply Voltage (V) Memory Type Memory Size (Bytes) Number of Time of Day Alarms Price**
DS1747  HH:MM:SS YYYY-MM-DD Bytewide 3.3
5 		NV SRAM 512K 0 $17.50 @ 1k
See All Timekeeping & Real-Time Clocks (86)
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 prices and delivery, please see the price and availability page or contact an authorized distributor.

Application Notes
  		• Application Note 504: Design Considerations for Dallas Semiconductor Real-Time Clocks - DS1747
  		• Application Note 507: PowerCap Package Allows for Density Upgrades, Surface Mount Assembly - DS1747
  		• Application Note 519: Using a Nonvolatile Timekeeping RAM with a Microcontroller - DS1747

    Evaluation Kits
    none

    Design Guides
  		• Real-Time Clocks (PDF)

    Reliability Reports
  		• Reliability Report: DS1747.pdf DS1747P.pdf
  		• Underwriters Laboratories (UL®) Recognized

    Software/Models
  		• DS1747WP120 IBIS Model

    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: 1-16 of 16

    DS1747 Notes Free
    Sample    		 Buy
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    		Temp RoHS/Lead-Free?
    Materials Analysis
    DS1747-70   5V, 70ns
    		0 pin;

    Use pkgcode/variation: MDT32-4*
    		0°C to +70°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747-70+  
    		0 pin;

    Use pkgcode/variation: MDT32+4*
    		0°C to +70°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747W-120+  
    		0 pin;

    Use pkgcode/variation: MDT32+4*
    		0°C to +70°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747W-120   3.3V, 120ns
    		0 pin;

    Use pkgcode/variation: MDT32-4*
    		0°C to +70°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747-70IND+  
    		0 pin;

    Use pkgcode/variation: MDT32+4*
    		-40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747W-120IND  
    		0 pin;

    Use pkgcode/variation: MDT32-4*
    		-40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747W-120IND+  
    		0 pin;

    Use pkgcode/variation: MDT32+4*
    		-40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747-70IND  
    		0 pin;

    Use pkgcode/variation: MDT32-4*
    		-40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747WP-120   3.3V, 120ns
    		0 pin;

    Use pkgcode/variation: PC2-1*
    		0°C to +70°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747WP-120+  
    		0 pin;

    Use pkgcode/variation: PC2+1*
    		0°C to +70°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747WP-120IND+  
    		0 pin;

    Use pkgcode/variation: PC2+1*
    		-40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747WP-120IND  
    		0 pin;

    Use pkgcode/variation: PC2-1*
    		-40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747P Notes Free
    Sample    		 Buy
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    		Temp RoHS/Lead-Free?
    Materials Analysis
    DS1747P-70   5V, 70ns
    		0 pin;

    Use pkgcode/variation: PC2-1*
    		0°C to +70°C RoHS/Lead-Free: No
    Materials Analysis
    DS1747P-70+  
    		0 pin;

    Use pkgcode/variation: PC2+1*
    		0°C to +70°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747P-70IND+  
    		0 pin;

    Use pkgcode/variation: PC2+1*
    		-40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS1747P-70IND  
    		0 pin;

    Use pkgcode/variation: PC2-1*
    		-40°C to +85°C RoHS/Lead-Free: No
    Materials Analysis

    More Information
  		• Real-Time Clock Design Guide (PDF)

    Related Products
    DS9034PCX PowerCap with Crystal

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    2006-11-30
    This page last modified: 2007-06-19




             


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