DESCRIPTION

The DS1245 1024k Nonvolatile SRAMs are1,048,576-bit, fully static, nonvolatile SRAMs organized as 131,072 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 DS1245 devices can be used in place of existing 128k x 8 static RAMs directly conforming to the popular bytewide 32-pin DIP standard. DS1245 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 128k x 8 volatile static RAM, EEPROM or Flash memory

■ Unlimited write cycles

■ Low-power CMOS

■ Read and write access times of 70 ns

■ Lithium energy source is electrically disconnected to retain freshness until power is applied for the first time

■ Full ±10% VCC operating range (DS1245Y)

■ Optional ±5% VCC operating range (DS1245AB)

■ 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 PowerCap allows easy removal using a regular screwdriver