ABSTRACT
As discussed so far, there is an almost continuous spectrum of different design approaches from design approaches with off-the-shelf packages, semi-custom design approaches, to the full-custom design approach, depending on the degree of the regularity of transistor arrangement in the layout and the simplification of realization of logic functions (i.e., whether logic functions are realized by a minimal sum or a logic network). Naturally, comparison of these approaches by many different criteria such as performance, design time, and chip size is very complex. Also, different design approaches are often mixed on the same chip, further complicating the comparison. Reliable comparison data are rarely available. But here we will try to give some idea of the advantages and disadvantages of the different design approaches.
