Patent ID: 7102411

Claim:
An RF circuit for receiving an input signal, and producing a differential mixer output signal using the input signal, comprising: a first plurality of transistors of a first type arranged in a ring configuration; a second plurality of transistors of a second type, wherein a source electrode of each of said second plurality of transistors is coupled to a drain electrode of a corresponding one of said first plurality of transistors and a drain electrode of each of said second plurality of transistors is coupled to a source electrode of said corresponding one of said first plurality of transistors, wherein the first and second plurality of transistors receive the input signal and a drive signal, and process the input signal and the drive signal to produce the differential mixer output signal having a frequency which is a function of frequency of the input signal and frequency of the drive signal, and wherein the drive signal includes an LO drive signal and a complementary LO drive signal; an LO buffer for producing the LO drive signal coupled to a control electrode of each of a first pair of said first plurality of transistors and each of a first pair of said second plurality of transistors and for producing the complementary LO drive signal coupled to a control electrode of each of a second pair of said first plurality of transistors and each of a second pair of said second plurality of transistors, wherein the LO buffer comprises a pair of input transistors; and an LO buffer bias circuit which is used to provide biasing voltages at gate electrodes of the input transistors, wherein said LO buffer comprises a high swing inductively loaded LO buffer, wherein the input transistors comprise a differential pair of LO buffer transistors, each coupled between a positive voltage source and ground through an inductive load, and wherein the LO buffer further comprises an LO buffer voltage limiter coupled to LO buffer outputs to limit common mode voltage ofthe LO drive signal and the complementary LO drive signal.