DESCRIPTION
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.

FEATURES
◾ 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
◾ Month and year determine the number of days in each month; 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 comparable 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