Abstract: The layout generation of analog devices is one of the key problems in analog layout automation．To optimize the performance，shape and area of the layout of MOS devices and to make the placement and routing easier at higher level，a new methodology for analog module generation is proposed．Based on geometry constraints，parasitic constraints and matching constraints，a module generator，Amodgen，is developed．Specifically，interdigitize structures，common centroid and interleave structures are used to minimize the mismatch between matched components in the layout．Dummy stripes are used to minimize boundary-dependent under-cut effects．