Johan P. Vanderhaegen and Robert W. Brodersen

Design Automation Conference, San Diego, June 2004

Abstract:

We present a method for designing operational amplifiers using reversed geometric programming, which is an extension of geometric programming that allows both convex and non-convex constraints. Adding a limited set of non-convex constraints can improve the accuracy of convex equation based optimization, without compromising global optimality. These constraints allow increased accuracy for critical modeling equations, such as the relationship between g_m and I_DS. To demonstrate the design methodology, a folded-cascode amplifier is designed in a 0.18 µm technology for varying speed requirements and is compared with simulations and designs obtained from geometric programming.