On changing the shape of ASIC based fully balanced analog system design

Two new and general methods of a fully balanced (FB) analog system design, which contribute towards achieving both a great reduction of the design time and a high performance system "implementation" are presented. It is shown that a single-ended system based on any type of op amps (rail-to-rail, constant g/sub m/, etc.), realized in any technology (CMOS, bilpolar, BiCMOS, GaAs), can be easily and effectively converted to its FB counterpart in a very practical way. Using the proposed rules, any FB system implementation with op amps (data converter, modulator, filter, etc.) requires only a single-ended system version design and the drawbacks related to a conventional FB system design are avoided. A final schematic/layout of a FB system can be achieved by pattern modification only of double single-ended system schematics/layouts, which are now available in the ASIC libraries of many companies.