Renesas Technology Corp.

Ttpcom Limited

Other

Takefumi Endo

Kazuo Watanabe

Taizo Yamawaki

Kazuaki Hori

Julian Hildersley

Toshinori Hirashima

Takao Sonobe

Kenji Hanada

In a PLL circuit, the number of LPFs is reduced to one to reduce mounting area and pin number, and to simplify design. In one embodiment, the PLL circuit includes a variable-gain phase comparator, a mixer, an LPF, VCOs, couplers, and a control circuit to controlling the on/off operation of the VCOs. The variable-gain phase comparator is capable of varying a phase difference gain. The on/off of the operation of the VCOs is controlled by the control circuit so that one of the VCOs is turned off. The phase difference conversion gain is varied in accordance with the sensitivity of the VCOs so the number of LPFs required for the PLL circuit can be reduced to only one.

PLL circuit and radio communication terminal apparatus using the same

Disclosed herein is a semiconductor device in which a main surface of a semiconductor chip is placed over a first main surface of a wiring board so as to be opposed thereto and which includes a plurality of external terminals provided over a second main surface of the wiring board. The plurality of external terminals have a plurality of signal terminals and a plurality of power terminals. The signal terminals are arranged along the periphery of the wiring board and the power terminals are arranged along the inside of a row of the signal terminals. Chip capacitors are placed over the main surface of the semiconductor chip, which lies inside a row of the power terminals. The plurality of signal terminals and power terminals formed over the main surface of the semiconductor chip are connected to a plurality of wires formed over the wiring board respectively. The wiring board is provided with an opening or recess which extends therethrough. The chip capacitors are located within the opening or recess. Thus, a reduction in switching noise can be achieved.

Semiconductor device and an electronic device

Growing community of inventors

Takasaki, Japan

Takefumi Endo