LC OSCILLATOR WITH SMALL OSCILLATION FREQUENCY VARIATIONS

摘要

In the LC oscillator circuit of the present invention, as to improve the yield to compensate for differences in the frequency characteristics, the LC oscillator circuit is applied to the control voltage on the basis of the inductor (1, 2), the digital control signal to a control voltage depending but having a variable capacitor unit which is the change in capacitance (12a, 12b) and the additional variable capacitor portion (13a, 13b) that the change in capacitance by the additional control voltage, the variable capacitor unit comprises: first through the K (K is an integer of 2 or more) to generate the first to control the voltage of the K as a control voltage according to the capacitor, and a digital control signal of having parts of a buffer to be applied to the variable capacitor of the first through the K, the k (k of the digital control signal selectively generating a first voltage buffer portion and a second lower voltage than the first voltage as the control voltage of the k in accordance with the logic of Me any integer of from 1 k) bits.