Patent ID: 7560997
Filing Date: 2009-07-14
Classification: H03L

Abstract:
1. A semiconductor integrated circuit device comprising: a phase locked loop; said phase locked loop including a phase comparator that compares a phase of a reference signal with a phase of an output signal of a frequency divider to detect phase difference therebetween, a voltage controlled oscillator that generates an oscillation signal controlled to render said phase difference constant, and said frequency divider that divides the frequency of said oscillation signal to output the resulting frequency divided signal to said phase comparator; said semiconductor integrated circuit device further comprising: a test signal input terminal device; a capacitive device connected between said test signal input terminal device and an input end of said frequency divider; and a control circuit connected to said test signal input terminal device; said control circuit exercising control so that, when a d.c. voltage is applied to said test signal input terminal device, a buffer circuit, connected to an output side of said voltage controlled oscillator, will not be in operations, wherein said capacitive device comprises a varactor diode arrangement.