Features and Benefits
- Real-Time Clock Keeps Track of Hundredths Of Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years
- 512k 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
- Over 10 Years of Data Retention in the Absence of Power
- Full 10% Operating Range
- Lithium Energy Source is Electrically Disconnected to Retain Freshness until Power is Applied for the First Time
- DIP Module Only
- Standard 32-Pin JEDEC Pinout
- Upward Compatible with the DS1248
- PowerCap Module Board Only
- Surface Mountable Package for Direct Connection to PowerCap Containing Battery and Crystal
- Replaceable Battery (PowerCap)
- Pin-for-Pin Compatible with Other Densities of DS124xP Phantom Clocks
The DS1251 4096K NV SRAM with Phantom Clock is a fully static nonvolatile RAM (organized as 512K words by 8 bits) with a built-in real-time clock. The DS1251Y 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 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 less 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.
Product Lifecycle Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Documentation & Resources
DS1251 Reliability Data1/12/2023
UG-52: Dallas Real Time Chip (RTC) Guide9/25/2002
How to Replace a DS1216 SmartSocket with an Equivalent-Density Phantom Clock Module10/1/2013
Lithium Battery Content in Maxim Products3/14/2011
Using the SmartWatch/Phantom Clocks with a Microcontroller7/9/2002
PowerCap Package Allows for Density Upgrades, Surface Mount Assembly5/30/2002
Design Considerations for Maxim Real-Time Clocks2/15/2002
DS1251 Companion Parts
Recommended Related Parts
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
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