A 6 ns 4 Mb ECL I/O BiCMOS SRAM with LV-TTL mask option

The authors report on a 4-Mb BiCMOS SRAM which achieves 6-ns and 8-ns access times with ECL (emitter coupled logic) and TTL (transistor-transistor logic) I/O interfaces, respectively, using: (1) a BinMOS converter directly connecting the ECL level to the CMOS level, (2) a high-speed BinMOS circuit with low-threshold voltage nMOSFETs, (3) an optimum word decoder, and (4) high-speed bipolar sensing circuits with a 3.3-V supply. The SRAM is applicable to either an ECL 100 K interface (VCC=0 V, VEE=4.5 V) or an LV-TTL interface (VCC=3.3 V, VEE=0 V), depending on the mask option used.<>