Patent ID: 6037825
Filing Date: 2000-03-14
Classification: H03D

Abstract:
A tree mixer mixing stage formed by a first transistor quad consisting of two differential pairs of transistors and a second transistor quad consisting of a further two differential pairs of transistors, the second transistor quad being complementary with respect to the first transistor quad; further comprising a first pair of input terminals for supplying a first differential input signal to both transistor quads, two second pairs of input terminals for supplying a second differential input signal to the first transistor quad and two third pairs of input terminals for supplying the second differential signal to the second transistor quad with a DC offset with respect to the second two pairs of input terminals, wherein the first transistor quad is connected to the second transistor quad through summing circuitry which includes an output for an output signals, the magnitude of the DC offset determining whether the mixing stage operates in Class A, class B or class AB.