Digital semiconductor variable capacitor

摘要

A novel semiconductor variable capacitor is presented. The semiconductor structure is simple and is based on a semiconductor variable capacitor with MOS compatible structure suitable for integrated circuits, which has at least three terminals, one of which is used to modulate the capacitance value between the other two terminals of the device, by increasing or decreasing its DC voltage with respect to one of the main terminals of the device. Furthermore, the present invention decouples the AC signal and the DC control voltage preventing distortion of the RF signal. The present invention describes a controllable capacitor whose capacitance value is not necessarily linear with its control voltage, but although possibly abrupt in its characteristic, is utilized to manufacture a semiconductor variable capacitor with digital control to improve its noise and linearity performance while maintaining high quality factor.

主权项

1. A digital semiconductor variable capacitor comprising:
a first equivalent capacitance plate; a second equivalent capacitance plate; at least one control region formed in a semiconductor region;
wherein said control region forms a rectifying junction with at least a portion of said semiconductor region;wherein the capacitance value between said first and second capacitance plates of said semiconductor variable capacitor is varied by varying a control voltage;wherein the variation of said control voltage causes a variation of the voltage drop across said rectifying junction, andwherein the variation of said capacitance value as a function of said control voltage is substantially digital.