Use of performance sensitivities in analog cell layout

The performance of analog circuits can be severely degraded to the point of violating design specifications if care is not taken during the layout phase. The authors discuss the importance of the sensitivities of the performance functions with respect to design parameters in guiding the layout process. Sensitivities quantify the performance degradation induced by changes in different design and process parameters. Hence, critical parameters can be easily detected. In this way, the layout design can be controlled in order to avoid excessive changes in these parameters. This will reduce the iterative design process imposed by the standard manual techniques. A new definition for sensitivity which reflects the design constraints is given. The sensitivities are generated, reduced, and compiled in a weighted graph that can be used to control the placement algorithm