Loop filter, phase locked loop and method of operating loop filter determining an amplitude of controlled voltage randomly

摘要

A method of operating a loop filter, a phase locked loop and a loop filter for randomly determining the amplitude of a control voltage is disclosed. A loop filter according to the present invention includes a timing adjusting clock generator and a variable capacitor unit. The timing adjustment clock generation unit generates a timing adjustment clock in which whether or not the first logic state appears is randomly determined. The variable capacitor unit is charged by the input current, and the capacitance changes in accordance with the logic state of the timing adjustment clock.