3.3 volt sense-amplifier schemes suitable for 4 Mb BiCMOS SRAMs

The authors propose and discuss sense amplifiers suitable for low voltage operation. Compared with a conventional current sensing scheme, the hierarchical voltage sensing scheme reduces sensing delay by 39% and improves functional minimum voltage to 1.8 V, which is sufficiently low for a 3.3-V static RAM (SRAM). High-speed sensing techniques for 4-Mb VLSI SRAMs and beyond, and performance of a 9-ns, 4-Mb transistor-transistor-logic input/output SRAM implementing one of these sense amplifiers, are also presented. >