DESCRIPTION
The DS1250 4096k Nonvolatile SRAMs are 4,194,304-bit, fully static, nonvolatile SRAMs organized as 524,288 words by 8 bits. Each complete NV SRAM 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 data corruption. DIP-package DS1250 devices can be used in place of existing 512k x 8 static RAMs directly conforming to the popular byte-wide 32-pin DIP standard. DS1250 devices in the PowerCap Module package are directly surface mountable and are normally paired with a DS9034PC PowerCap to form a complete Nonvolatile SRAM module. There is no limit on the number of write cycles that can be executed and no additional support circuitry is required for microprocessor interfacing.

FEATURES
■ 10 years minimum data retention in the
absence of external power
■ Data is automatically protected during power loss
■ Replaces 512k x 8 volatile static RAM, EEPROM or Flash memory
■ Unlimited write cycles
■ Low-power CMOS
■ Read and write access times of 70ns
■ Lithium energy source is electrically
   disconnected to retain freshness until power is
   applied for the first time
■ Full ±10% VCC operating range (DS1250Y)
■ Optional ±5% VCC operating range (DS1250AB)
■ Optional industrial temperature range of
   -40°C to +85°C, designated IND
■ JEDEC standard 32-pin DIP package
■ PowerCap Module (PCM) package
   - Directly surface-mountable module
   - Replaceable snap-on PowerCap provides lithium backup battery
   - Standardized pinout for all nonvolatile SRAM products
   - Detachment feature on PCM allows easy removal using a regular screwdriver