Chip-Package Co-Design of Integrated Mixed Signal Systems

The Noise Figure of a Low Noise Amplifier is a function of the quality factor of its inductors. The lack of high-Q inductors in silicon has prevented the development of completely integrated CMOS LNAs for high sensitivity applications like GSM (1.9 GHz) and W-CDMA (2.1 GHz). Recent developments in the design of high-Q inductors (embedded in low cost IC packages) have made single-package integration of RE frontends feasible. These embedded passives provide a viable alternative to using discrete elements or low-Q on-chip passives, for achieving completely integrated solutions. Compared to on-chip inductors with low Q values and discrete passives with fixed Q's, the use of these embedded passives also leads to the development of the passive Q as a new variable in circuit design. However, higher Q values also result in new tradeoffs,particularly with respect to device size. This paper presents a novel optimization strategyfor the design of completely integrated CMOS LNAs using embedded passives. Thetradeoff of higher inductor size for higher Q has been adopted into the LNA designmethodology. The paper also presents design issues involved in the use of multipleembedded components in the packaging substrate, particularly with reference to mutualcoupling between the passives and reference ground layout.