Design of fully balanced analog systems based on ordinary and/or modified single-ended opamps

The system architectures, which allow a high performance fully balanced (FB ) system based on ordinary/modified single-ended opamps to be implemented, are investigated and the basic and general requirements are formulated. Two new methods of an FB analog system design, which contribute towards achiev ing both a high performance IC system implementation and a great reduction of the design time are presented. It is shown that a single-ended system ba sed on any type of opamp (rail-to-rail, constant g(m), etc.), realized in a ny technology (CMOS, bipolar, 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 opamps (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. The princ iples of the design are pointed out and they are verified by experimental r esults.