DS1746P

Y2K-Compliant, Nonvolatile Timekeeping RAMs


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Description

The DS1746 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 128k x 8 nonvolatile static RAM. User access to all registers within the DS1746 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 DS1746 also contains its own power-fail circuitry, which 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.
DS1746, DS1746P: Block Diagram DS1746, DS1746P: Block Diagram Enlarge+

Key Features

  • Integrated NV SRAM, Real-Time Clock, 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 (i.e., 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 128k 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
Part NumberInterfaceVSUPPLY
(V)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsFunctionsPackage/PinsBudgetary
Price
See Notes
DS1746 Bytewide
3.3
5
NV SRAM128K0RTC
MOD/32
PWRCP/34
$20.00 @1k
See All Timekeeping & Real-Time Clocks (77)
Pricing 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 and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Quality and Environmental Data

Product Reliability Reports: DS1746P.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 >

 
Status:
Package:
Temperature:

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05/29/2020 - 05/31/2020, Detroit, MI
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