GENERAL DESCRIPTION

The HMN1M8D Nonvolatile SRAM is a 8,388,608-bit static RAM organized as 1,048,576 bytes by 8 bits. The HMN1M8D has a self-contained lithium energy source provide reliable non-volatility coupled with the unlimited write cycles of standard SRAM and integral control circuitry which constantly monitors the single 5V supply for an out-oftolerance condition. When such a condition occurs, the lithium energy source is automatically switched on to sustain the memory until after VCC returns valid and write protection is unconditionally enabled to prevent garbled data. In addition the SRAM is unconditionally write-protected to prevent an inadvertent write operation. At this time the integral energy source is switched on to sustain the memory until after VCC returns valid.

The HMN1M8D uses extremely low standby current CMOS SRAM’s, coupled with small lithium coin cells to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM.

FEATURES

♦ Access time : 70, 85, 120, 150 ns

♦ High-density design : 8Mbit Design

♦ Battery internally isolated until power is applied

♦ Industry-standard 36-pin 1,024K x 8 pinout

♦ Unlimited write cycles

♦ Data retention in the absence of VCC

♦ 10-years minimum data retention in absence of power

♦ Automatic write-protection during power-up/power-down cycles

♦ Data is automatically protected during power loss