Patent ID: 7386064
Filing Date: 2008-06-10
Classification: H03L

Abstract:
1. A communication semiconductor integrated circuit device with a PLL circuit having a phase detecting circuit for detecting a phase difference between a signal having a predetermined frequency and a feedback signal, a charge pump and a filter capacitor for generating a voltage corresponding to the phase difference detected by the phase detecting circuit, and an oscillator circuit for performing an oscillation operation in accordance with the voltage across the filter capacitor, comprising first and second registers which output control values set therein, wherein the charge pump includes a plurality of first current sources which are controlled in accordance with outputs of the phase detecting circuit, and a plurality of second current sources which are controlled in accordance with outputs of the first and second registers, in the first register, the control value for selecting one of the second current sources to be turned on is set, in the second register, the control value for selecting an initial voltage at start-up of the PLL circuit is set, the PLL circuit has a plurality of pull-in operation modes which are controlled in accordance with the outputs of the first and second registers, for pulling the voltage across the filter capacitor in a lock-up voltage in response to an activation of the PLL circuit, and performs the pull-in operation in accordance with a setting value in the first register for designating one of the plurality of pull-in operation modes.