Calibrated PLL for wide band communication semiconductor integrated polar loop transmitter

摘要

The invention provides a communication semiconductor integrated circuit (RF IC) that, when a transmission oscillator is incorporated into a semiconductor chip, secures the oscillation operation over a wide frequency range, prevents a deterioration of a transmission spectrum, and thereby enhances the accuracy of an oscillation frequency. The integrated circuit corrects a dispersion of the KV characteristic of the transmission oscillator by calibrating a current Icp of the charge pump inside the phase control loop. More in concrete, the integrated circuit measures a KV value Kv of the transmission oscillator, and calibrates the current Icp of the charge pump so that Kv.Icp falls into a predetermined value.