The DS1254 is a fully nonvolatile static RAM (NV SRAM) (organized as 2M words by 8 bits) with built-in real-time clock. It has a self-contained lithium energy source and control circuitry that constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the DS1254 makes use of an attached DS3800 battery cap to maintain clock information and preserve stored data while protecting that data by disallowing all memory accesses. Additionally, the DS1254 has dedicated circuitry for monitoring the status of an attached DS3800 battery cap.
The phantom clock provides timekeeping information including hundredths of seconds, seconds, minutes, hours, day, date, month, and year information. 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.
Because the DS1254 has a total of 168 balls and only 35 active signals, balls are wired together into groups, thus providing redundant connections for every signal.
Key Features
Applications/Uses
Real-Time Clock (RTC) Keeps Track of Hundredths of
Seconds, Seconds, Minutes, Hours, Days, Date,
Months, and Years with Automatic Leap-Year
Compensation Valid Up to the Year 2100
2M x 8 NV SRAM
Watch Function is Transparent to RAM Operation
Automatic Data Protection During Power Loss
Unlimited Write-Cycle Endurance
Surface-Mountable BGA Module Construction
Over 10 Years of Data Retention in the Absence of
Power
* 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.
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