BQ4011 32Kx8 Nonvolatile SRAM

Description

The CMOS bq4011 is a nonvolatile 262,144-bit static RAM organized as 32,768 words by 8 bits. The integral control circuitry and lithium energy source provide reliable nonvolatility coupled with the unlimited write cycles of standard SRAM. The control circuitry constantly monitors the single 5V supply for an out-of-tolerance condition. When VCC falls out of tolerance, the SRAM is unconditionally write-protected to prevent inadvertent write operation. At this time the integral energy source is switched on to sustain the memory until after VCC returns valid. 

The bq4011 uses an extremely low standby current CMOS SRAM, coupled with a small lithium coin cell to provide nonvolatility without long write-cycle times and the write-cycle limitations associated with EEPROM. The bq4011 requires no external circuitry and is socket-compatible with industry-standard SRAMs and most EPROMs and EEPROMs.

Features 

• Data retention in the absence of power 

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

• Industry-standard 28-pin 32K x 8 pinout 

• Conventional SRAM operation; unlimited write cycles 

• 10-year minimum data retention in absence of power 

• Battery internally isolated until power is applied