Hitachi, Ltd.

Akita Electronics Systems Co., Ltd.

Satoru Takahashi

Kazuhiro Tagawa

Norio Hayashi

Ikuya Ono

Ikuya Ohno

Masachika Ohno

The semiconductor integrated circuit (RF IC) for a mobile telephone capable of transmitting/receiving the signals of plural bands reduces the DC offsets of the amplifiers located in the following stages of the mixers that demodulate or down-convert the reception signals. The invention scrambles the signal lines to transmit the outputs of the plural mixers that demodulate or down-convert the reception signals of different bands, so as to avoid the adjacent signal lines from making the same combination from the starting ends to the finishing ends.

Semiconductor integrated circuit device

The thermal interference due to the self heating of transistors constituting a gilbert cell circuit is reduced, thereby largely improving the receiving sensitivity to signals. A mixer circuit composed of a gilbert cell circuit comprises transistors Tto T. Each of the transistors Tto Tis con figured so that four transistors may be connected in parallel. In a layout on a semiconductor chip, four transistors Tto Tand Tto Trespectively constituting the transistors Tand Tare respectively separated into two pairs, and the respective two pairs are laid out in a crisscross shape so that they are crossed with each other. Similarly, four transistors Tto Tand Tto Trespectively constituting the transistors Tand Tare respectively separated into two pairs, and the respective two pairs are laid out in a crisscross shape so that they are crossed with each other. Thus, the thermal influence applied on the transistors Tto Tis uniformed.

Growing community of inventors

Takasaki, Japan

Satoru Takahashi