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