Direct replacement of silicon ECL and TTL SRAMs with high performance GaAs devices

Most high-speed GaAs SRAMs (static random-access memories) previously reported require nonstandard power supplies, and/or operate in a narrow temperature range. The authors describe two 1 K (256*4) SRAMS, one with TTL (transistor-transistor logic) I/O and the other with ECL (emitter-coupled logic) I/O. These are drop-in replacements for the industry standard parts 93422 and 100422. They both require one single standard supply source and are designed with sufficient margins to operate over a wide temperature and supply range. These RAMs are fabricated with E/D (enhancement/depletion) MESFET technology, and functionality yields of 50% are typically obtained. Access time as low as 2.5 ns has been measured on these RAMS. Worst-case t/sub AA/ measured was 4 ns for the TTL I/O RAM and 3 ns for the ECL I/O RAM at room temperature. The RAMs are functional at case temperature from -5 to +85 degrees C, with 10% supply variation. Power dissipation is approximately 1.5 W for both RAMs.<>