Patent ID: 6889037

Claim:
A mixer, comprising: first and second MOSFETs having source terminals coupled together; a first input MOSFET coupled to the source terminals of the first and second MOSFETs to operate as a first bias current sink for the first and second MOSFETs and coupled to receive a first leg of a small differential signal input; third and fourth MOSFETs having source terminals coupled together wherein the drain terminals of the first and third MOSFETs are coupled together to provide a first leg of a differential output of the mixer and the drain terminals of the second and fourth MOSFETs are coupled together to provide a second leg of the differential output; a second input MOSFET coupled to the source terminals of the third and fourth MOSFETs to operate as a second bias current sink for the third and fourth MOSFETs and coupled to receive a second leg of the small differential signal input; wherein the first and fourth MOSFETs have gate terminals operatively coupled to receive a first leg of a large signal differential input; wherein the second and third MOSFETs have gate terminals operatively coupled to receive a second leg of a large signal differential input; at least one current source; and first and second coupling MOSFETs operably coupled to the at least one current source and to the first and second input MOSFETs, respectively, to substantially source the first and second bias currents when the large signal differential input approaches an alternating current zero-crossing point, the first and second coupling MOSFETs further coupled to receive, at a gate terminal of each of the first and second coupling MOSFETs, a signal from the source terminals of the third and fourth MOSFETs and the first and second MOSFETs, respectively, to operationally bias the first and second coupling MOSFETs.