DS1747, DS1747P:Y2K-Compliant, Nonvolatile Timekeeping RAMs

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
DS1747, DS1747P: Block Diagram
DS1747, DS1747P: Block Diagram
DataSheet
titleDownload file
DS1747-DS1747P Data SheetDS1747-DS1747P.pdf
Parametrics
Part NumberInterfaceVSUPPLY
(V)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsFunctionsPackage/PinsBudgetary
Price
See Notes
DS1747Bytewide3.3
5
NV SRAM512K0RTCEDIP/32
PCAP/34
$24.40 @1k
Quality and Environmental Data
Related Products
Ordering Information
Part NumberNotesStatusRecommended ReplacementPackageTempRoHS
DS1747-705V, 70nsNo Longer AvailableDS1747-70+EDIP,;32 pin;707.2 mm²0°C to +70°CSee data sheet
DS1747-70+ActiveEDIP,;32 pin;707.2 mm²0°C to +70°CLead Free
DS1747-70INDNo Longer AvailableDS1747-70IND+EDIP,;32 pin;707.2 mm²-40°C to +85°CSee data sheet
DS1747-70IND+ActiveEDIP,;32 pin;707.2 mm²-40°C to +85°CLead Free
DS1747P-705V, 70nsNo Longer AvailableDS1747P-70+PCAP,;34 pin;596.9 mm²0°C to +70°CSee data sheet
DS1747P-70+ActivePCAP,;34 pin;596.9 mm²0°C to +70°CLead Free
DS1747P-70INDNo Longer AvailableDS1747P-70IND+PCAP,;34 pin;596.9 mm²-40°C to +85°CSee data sheet
DS1747P-70IND+ActivePCAP,;34 pin;596.9 mm²-40°C to +85°CLead Free
DS1747W-1203.3V, 120nsNo Longer AvailableDS1747W-120+EDIP,;32 pin;707.2 mm²0°C to +70°CSee data sheet
DS1747W-120+ActiveEDIP,;32 pin;707.2 mm²0°C to +70°CLead Free
Part NumberNotesStatusRecommended ReplacementPackageTempRoHS
DS1747W-120INDNo Longer AvailableDS1747W-120IND+EDIP,;32 pin;707.2 mm²-40°C to +85°CSee data sheet
DS1747W-120IND+ActiveEDIP,;32 pin;707.2 mm²-40°C to +85°CLead Free
DS1747WP-1203.3V, 120nsNo Longer AvailableDS1747WP-120+PCAP,;34 pin;596.9 mm²0°C to +70°CSee data sheet
DS1747WP-120+ActivePCAP,;34 pin;596.9 mm²0°C to +70°CLead Free
DS1747WP-120INDNo Longer AvailableDS1747WP-120IND+PCAP,;34 pin;596.9 mm²-40°C to +85°CSee data sheet
DS1747WP-120IND+ActivePCAP,;34 pin;596.9 mm²-40°C to +85°CLead Free
DS1747WP-C01No Longer AvailableDS1747WP-120+PCAP,;34 pin;596.9 mm²0°C to +70°CSee data sheet
DS1747-DS1747P.pdf DS1747
Tips for Writing Bulletproof Real-Time Clock Control Code DS3234
State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks DS3234
Using a Nonvolatile Timekeeping RAM with a Microcontroller DS1747
PowerCap Package Allows for Density Upgrades, Surface Mount Assembly DS9034PCX
Design Considerations for Maxim Real-Time Clocks DS3234
DS1747P.pdf DS1747
DS1747.pdf DS1747
DS1747-DS1747P.pdf DS1747P