Automatic gain control (AGC) circuit for high density BiCMOS SRAM

BiCMOS technolory has been ~ioven to be most effective for improving the performance of SRAMs. A sub 10"s access time has been reported in jl BiCMOS SRAM of IMeg bit density I] In addition to performance advantaaes. the availability of birk transistors in &CMOS technology has triggered an evolutibn of BiCMOS de"!" techniques for improving margin and minimining process sensitivity of Ultra Large Scale IC's. In this paper an Automatic Gain Control (AGC) circuit is discussed. This AGC circuit is applied to a high speed RiCMOS SRAM bitline scheme to control the bitline voltage swings BO that they are independent or temperature, operation and pmcess variations. Utilization of the superior small signal amplification eapabilitu of bioolar tranristor differential sense L~DB to directly coude