A temperature- and process-tolerant 64K EEPROM

A 64K EEPROM is described with emphasis on the circuit techniques used to achieve extended temperature operation. The core architecture is considered and a suitable byte layout which eliminates possible punchthrough in the memory cell is shown. A feedback-controlled substrate bias generator is described which delivers -1.0 V/spl plusmn/0.05 V and reduces significantly field transistor leakages. In addition, a /spl plusmn/1% stable voltage reference is shown to accurately control the programming voltage for the memory array to 20 V/spl plusmn/1 V over the full military temperature range (-55/spl deg/-+125/spl deg/C) and /spl plusmn/10% power-supply variation. A process-insensitive write timing pulse trimmed by E2 fuses is discussed, as is the PAGE-MODE WRITE circuitry in relation to the bitline latches.