The DS1244Y-70+ is a 256K NV SRAM with Phantom clock in 28 pin EDIP package. The 256K NV SRAM with a Phantom clock is a fully static non-volatile 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, 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 for hundredths of seconds, seconds, minutes, hours, days, date, months and years. 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.