Patent ID: 6704559
Filing Date: 2004-03-09
Classification: H03D,H04B

Abstract:
An RF mixer circuit having reduced intermodulation products comprising:a) a cascode transconductance amplifier with inductive emitter degeneration including a first transistor having a control electrode connected to receive an input RF signal and serially connected with a second transistor having a control electrode connected to receive a bias potential; b) a balanced mixer coupled to the second transistor by a first inductive element for receiving an amplified input signal and receiving a signal from a local oscillator and producing an output signal with an intermediate frequency related to the frequencies of the amplifier input signal and the local oscillator, and c) a feedback circuit from the second transistor to the control electrode of the first transistor including a resistor serially connected with a capacitor, whereby the feedback circuit compensates for signal phase shift by the inductive element so that the IM3 products are cancelled out.