Patent Number: 7,103,337

Title: PLL circuit having a multi-band oscillator and compensating oscillation frequency

Abstract: A semiconductor integrated circuit device for communication is provided with a PLL circuit or the like formed therein, the PLL circuit which is capable of realizing the compensation of fluctuation due to temperature change, the inhibition of increase in the chip area and the ensurement of the performance margin, and which controls a VCO having multiple oscillation frequency bands. In the case where automatic calibration is performed by switching a switch to a side of a DC voltage source in the PLL circuit using a VCO having multiple oscillation bands, a tuning voltage (Vtune) of an RFVCO is fixed to a voltage value of a DC voltage source. However, since a temperature characteristic of canceling a VCO oscillation frequency is given to the DC voltage source, it is possible to minimize the influence on the band selection when a calibration table comes to no optimum one.

Inventors: Uozumi; Toshiya (Takasaki, JP), Tanaka; Satoshi (Tamamura, JP), Kasahara; Masumi (Takasaki, JP), Oosawa; Hirotaka (Isesaki, JP), Kimura; Yasuyuki (Maebashi, JP), Henshaw; Robert Astle (Sudbury, GB)

Assignee: Hitachi, Ltd.

International Classification: H04B 1/06 (20060101)

Expiration Date: 9/05/02018