DESCRIPTION
The STK16C68 is a fast SRAM with a nonvolatile EEPROM element incorporated in each static memory cell. The SRAM can be read and written an unlimited number of times, while independent nonvolatile data resides in EEPROM. Data transfers from the SRAM to the EEPROM (the STORE operation) can take place automatically on power down. An internal capacitor guarantees the STORE operation regardless of power down slew rate. Transfers from the EEPROM to the SRAM (the RECALL operation) take place automatically on restoration of power. Initiation of STORE and RECALL cycles can also be controlled by entering control sequences on the SRAM inputs. The STK16C68 is pin-compatible with 8k x 8 SRAMs and battery-backed SRAMs, allowing direct substitution while enhancing performance. The STK12C68, which uses an external capacitor, and the STK15C68, which uses charge stored in system capacitance, are alternatives for systems needing AutoStore™ operation.

FEATURES
• Transparent Data Save on Power Down
• Internal Capacitor Guarantees AutoStore™ Regardless of Power-Down Slew Rate
• Nonvolatile Storage without Battery Problems
• Directly Replaces 8K x 8 Static RAM, Battery Backed RAM or EEPROM
• 20ns, 25ns, 35ns and 45ns Access Times
• STORE to EEPROM Initiated by Software or AutoStorePlus™ on Power Down
• RECALL to SRAM Initiated by Software or Power Restore
• 10mA Typical ICC at 200ns Cycle Time
• Unlimited READ, WRITE and RECALL Cycles
• 1,000,000 STORE Cycles to EEPROM
• 100-Year Data Retention over Full Industrial Temperature Range
• No Data Loss from Undershoot
• Commercial and Industrial Temperatures
• 28-Pin 600 mil PDIP and 350 mil SOIC Packages