DESCRIPTION
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.

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
■ Month and year determine the number of days in each month; valid up to 2100
■ Full 10% operating range
■ Operating temperature range: 0
C to +70
C
■ 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
■ Underwriters Laboratory (UL) recognized