DESCRIPTION

The DS1230 256k Nonvolatile SRAMs are 262,144-bit, fully static, nonvolatile SRAMs organized as 32,768 words by 8 bits. Each 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 DS1230 devices can be used in place of existing 32k x 8 static RAMs directly conforming to the popular bytewide 28-pin DIP standard. The DIP devices also match the pinout of 28256 EEPROMs, allowing direct substitution while enhancing performance. DS1230 devices in the Low Profile Module package are specifically designed for surface-mount applications. 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 32k x 8 volatile static RAM, EEPROM or Flash memory

■ Unlimited write cycles

■ Low-power CMOS

■ Read and write access times as fast as 70 ns

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

■ Full ±10% VCC operating range (DS1230Y)

■ Optional ±5% VCC operating range (DS1230AB)

■ Optional industrial temperature range of -40°C to +85°C, designated IND

■ JEDEC standard 28-pin DIP package

■ New 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