DS1244:256k NV SRAM with Phantom Clock

The DS1244 256k NV SRAM with a Phantom clock is a fully static nonvolatile RAM (NV SRAM) (organized as 32k words by 8 bits) with a built-in real-time clock. The DS1244 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock. The phantom clock provides timekeeping information for hundredths of seconds, seconds, minutes, hours, days, date, months, and years. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

Key Features
  • Real-Time Clock (RTC) Keeps Track of Hundredths of Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years
  • 32k x 8 NV SRAM Directly Replaces Volatile Static RAM or EEPROM
  • Embedded Lithium Energy Cell Maintains Calendar Operation and Retains RAM Data
  • Watch Function is Transparent to RAM Operation
  • Automatic Leap Year Compensation Valid Up to 2100
  • Full 10% Operating Range
  • Over 10 Years of Data Retention in the Absence of Power
  • Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is Applied for the First Time
  • DIP Module Only
  • Standard 28-Pin JEDEC Pinout
  • PowerCap Module Board Only
    • Surface mountable package for direct connection to PowerCap containing battery and crystal
    • Replaceable battery (PowerCap)
    • Pin-for-pin compatible with DS1248P and DS1251P
  • Available in Lead-Free Package
DS1244, DS1244P: Typical Operating Circuit
DS1244, DS1244P: Typical Operating Circuit
DataSheet
titleDownload file
DS1244-DS1244P Data SheetDS1244-DS1244P.pdf
Parametrics
Part NumberInterfaceVSUPPLY
(V)
Memory TypeMemory Size
(Bytes)
Time of Day AlarmsFunctionsPackage/PinsBudgetary
Price
See Notes
DS1244Bytewide
Phantom Clock
3.3
5
NV SRAM32K0RTCEDIP/28
PCAP/34
$16.77 @1k
Quality and Environmental Data
Related Products
Ordering Information
Part NumberStatusRecommended ReplacementPackageTempRoHS
DS1244W-120No Longer AvailableDS1244W-120+EDIP,;28 pin;629.9 mm²0°C to +70°CSee data sheet
DS1244W-120+ActiveEDIP,;28 pin;629.9 mm²0°C to +70°CLead Free
DS1244W-120IND+ActiveEDIP,;28 pin;629.9 mm²-40°C to +85°CLead Free
DS1244WP-120No Longer AvailableDS1244WP-120+PCAP,;34 pin;596.9 mm²0°C to +70°CSee data sheet
DS1244WP-120+ActivePCAP,;34 pin;596.9 mm²0°C to +70°CLead Free
DS1244WP-120IND+ActivePCAP,;34 pin;596.9 mm²-40°C to +85°CLead Free
DS1244Y-70No Longer AvailableDS1244Y-70+EDIP,;28 pin;629.9 mm²0°C to +70°CSee data sheet
DS1244Y-70+ActiveEDIP,;28 pin;629.9 mm²0°C to +70°CLead Free
DS1244YP-70+ActivePCAP,;34 pin;596.9 mm²0°C to +70°CLead Free
DS1244-DS1244P.pdf DS1244
Tips for Writing Bulletproof Real-Time Clock Control Code DS3234
How to Replace a DS1216 SmartSocket with an Equivalent-Density Phantom Clock Module DS1251
State Machine Logic in Binary-Coded Decimal (BCD)-Formatted Real-Time Clocks DS3234
Using the SmartWatch/Phantom Clocks with a Microcontroller DS1315
PowerCap Package Allows for Density Upgrades, Surface Mount Assembly DS9034PCX
Design Considerations for Maxim Real-Time Clocks DS3234
Using the Dallas Phantom Real-Time Clocks (RTCs) DS1315
DS1244.pdf DS1244
DS1244-DS1244P.pdf DS1244