ABSTRACT
The design of monolithic transformers for RF and mm-wave circuit applications are described in this chapter. On-chip transformers are applied to radio front-ends as VCO resonators, low-loss feedback networks, baluns, power combiners/splitters, and even ESD protection networks for wideband inputs. Transformer insertion loss, transformation ratio, and design for a specific bandwidth are outlined. Methods for shielding, which are essential to reduce substrate losses from on-chip transformers at mm-wave frequencies, are also described. Small- and large-signal models for simulation of circuits in a typical design flow are presented. Application-specific aspects of transformer design for VCOs, LNAs, and power amplifiers are detailed throughout using mm-wave case studies as design examples.
