Extraction of feedback information from circuit netlists

Abstract

For a successful analog/mixed signal design, various layout constraints have to be seriously addressed, which is one of the reasons why automatic design of analog layouts is intrinsically more difficult than that of digital layouts. Since feedback has long been a mysterious effect in virtually all analog integrated circuits, improving on constraint file can be done according to feedback information. In this paper, the technique of feedback circuit extraction (FCE) is presented, which is the transformation of feedback design descriptions from circuit level to functional level. Novelly, the algorithm of FCE utilizes the direction of signal flow to extract detailed information of intentional feedback network