Patent ID: 7956666

Claim:
A mixer, comprising: a transconductor circuit, receiving a differential voltage signal to generate and to output a differential current signal; a first switch circuit coupled to the transconductor circuit to regulate the differential current signal in response to a first oscillator signal; a first load circuit coupled to the first switch circuit, comprising: a first transistor and a second transistor, wherein drains of the first and second transistors are coupled to the first switch circuit to form a first differential output end; a first resistor coupled between a gate and the drain of the first transistor; and a second resistor coupled between a gate and the drain of the second transistor; a second switch circuit coupled to the transconductor circuit to regulate the differential current signal in response to a second oscillator signal; and a second load circuit coupled to said second switch, comprising: a third transistor and a fourth transistor, wherein drains of the third and fourth transistors are coupled to the second switch circuit to form a second differential output end; a third resistor coupled between a gate and the drain of the third transistor; and a fourth resistor coupled between a gate and the drain of the fourth resistor; wherein the first load circuit and the second load circuit are connected at a common node; wherein the gates of the first transistor, the second transistor, the third transistor, and the fourth transistor are connected to form the common node.