A method for designing analog circuits in which topological design is followed by simultaneous device sizing and layout design is described. By merging circuit and layout design into a single design process, analog circuits can be optimally designed taking layout parasitics fully into account. Using the method, a CMOS operational-amplifier compiler (OAC) has been developed. Given a set of performance specifications and process parameters, OAC generates a layout with circuit performance optimized to meet specified performance constraints. A procedural layout technique is employed to generate a compact and practical layout. A nonlinear optimization method for device sizing which relies on the results of simulations based on the circuit extracted from the layout is applied. Design experiments have shown that OAC can produce satisfactory results with respect to both circuit performance and layout density. >