Patent ID: 7840195

Claim:
A multifunction RF circuit comprising, on a single semiconductor chip, a power amplifier circuit, a mixer circuit forming an integral part of said power amplifier circuit and a low-pass filter circuit; wherein said power amplifier circuit comprises a first amplifying branch comprising a first input and a first output, and a second amplifying branch comprising a second input and a second output; wherein said first amplifier circuit includes a first shared transistor operably connected between the first input and the first output and a first resistor connected between the first input and the first output and said second amplifying branch includes a second shared transistor operably connected between said second input and said second output and a second resistor connected between the second input and the second output, said first and second shared transistors being configured to amplify signals received at the first and the second inputs, respectively, said first and second shared transistors each including an n-channel MOSFET and a p-channel MOSFET, wherein a further circuit comprising a series connection of a first inductor, a capacitor and a second inductor is connected between said first output and said second output, and wherein said mixer circuit includes said first shared transistor and said second shared transistor, said first and second shared transistors being configured to generate mixing signals at the first and the second outputs, respectively, said mixing signals being based on said signals received at the first and the second inputs, respectively.