Patent ID: 7514981

Claim:
A mixer is a small signal differential model, comprising: a load circuit; a switch quad, coupled to the load circuit, including a first current path and a second current path; and a transconductor including a first resistor, a first operational amplifier, a second operational amplifier, a first current mirror, and a second current mirror, wherein an output terminal of the first operational amplifier is directly connected to the first current mirror, an output terminal of the second operational amplifier is directly connected to the second current mirror, the first resistor is coupled between a positive input terminal of the first operational amplifier and a positive input terminal of the second operational amplifier, a current control terminal of the first current mirror is directly connected to the positive input terminal of the first operational amplifier, a current mirroring terminal of the first current mirror is coupled to the first current path, a current control terminal of the second current mirror is directly connected to the positive input terminal of the second operational amplifier, a current mirroring terminal of the second current mirror is coupled to the second current path, and a negative input terminal of the first operational amplifier and a negative input terminal of the second operational amplifier are capable of receiving a voltage signal.