Abstract: An integrated circuit device for frequency conversion in a CATV tuner, in which the signal output from an oscillation circuit section has an improved phase noise characteristic. The mixer circuit section, including an RF input port, an LO input port, and an IF output port, and an oscillation circuit section connected to the LO input port of the mixer circuit section, may be formed on one semiconductor substrate, or on separate substrates. The mixer circuit section uses an FET as a nonlinear element and the oscillation circuit section uses a bipolar transistor as an oscillation element. By this constitution the phase noise of the signal outputted from the oscillation circuit section can be made small.

Abstract: A double-balanced mixer which includes four diodes effectively connected to each other in a bridge connection on a substrate. The four diodes are formed into two sets of diodes, each one set including two of the four diodes connected to the same input line, with two twin-diodes each including two of the four diodes formed on the same semi-conductor chips being used for the two sets of the diodes.