Patent ID: 6057714
Filing Date: 2000-05-02
Classification: H03D

Abstract:
A circuit comprising a double balance differential active ring mixer with a current shared active input balun, the circuit being configured to be coupled to a bias circuit for providing a relatively constant current and a buffer circuit for receiving a signal from a local oscillator (LO) source and generating differential LO signals, the circuit including:(a) an input node for receiving an input signal;(b) the balun circuit including:(1) a common gate amplifier having a source, a drain, and a gate, the source being coupled to the input node, the gate being DC coupled to be bias circuit and AC coupled, directly or indirectly, to ground, and the drain comprising a first output;(2) a common source amplifier having a source, a drain, and a gate, the source being DC coupled to ground, the gate being coupled to the bias circuit and the input node, and the drain comprising a second output;(3) an impedance coupled to the drain of the common source amplifier for compensating any difference in output or voltage gain between the common gate amplifier and the common source amplifier; and(c) the mixer being coupled to the first and second differential outputs and the differential LO signals, such that the mixer is adapted for generating differential intermediate frequency outputs.