X24C45 pdf datasheet (Serial A

The Intersil X24C45 is a serial 256-bit NOVRAM featuring
a static RAM configured 16 x 16, overlaid bit-by-bit
with a nonvolatile EEPROM array. The X24C45 is fabricated
with Intersil’s Advanced CMOS Floating Gate
technology.
The Intersil NOVRAM design allows data to be transferred
between the two memory arrays by means of
software commands or external hardware inputs. A
store operation (RAM data to EEPROM) is completed
in 5ms or less and a recall operation (EEPROM data to
RAM) is completed in 2μs or less.
The X24C45 also includes the AUTOSTORE feature, a
user selectable feature that automatically performs a
store operation when VCC falls below a preset threshold.
Intersil NOVRAMs are designed for unlimited write
operations to RAM, either from the host or recalls from
EEPROM and a minimum 1,000,000 store operations.
Inherent data retention is specified to be greater than
100 years.