Renesas Technology Corp.

Hitachi, Ltd.

Akita Electronics Systems Co., Ltd.

Ikuya Ono

Toshiya Uozumi

Jiro Shinbo

Satoru Takahashi

Kazuhiro Tagawa

Tamotsu Takahashi

The present invention provides a semiconductor integrated circuit for communication (RF IC) operable in a mode for receiving a received signal subjected to phase modulation and amplitude modulation and a mode for receiving a received signal subjected only to phase modulation. In the semiconductor integrated circuit for communication, a frequency band of a loop filter in a PLL circuit is switched and set so as to become large in a reception mode and become small in a transmission mode.

Semiconductor integrated circuit for communication and terminal device for mobile communication

A receiving circuit of a direct conversion system is provided which includes a differential amplifier circuit which amplifies a received signal, a mixer which combines the amplified received signal and an oscillation signal having a predetermined frequency to thereby perform frequency conversion, and a high gain amplifier circuit in which a plurality of programmable gain amplifiers and a plurality of filters which eliminate noise of the received signal and an unnecessary wave, are connected in a multistage and which is configured such that an amplification factor is varied according to the level of the received signal. In the receiving circuit, the low noise amplifier is brought to a non-operating state to thereby allow execution of a DC offset cancel operation of the corresponding programmable gain amplifier on the pre-stage side of the high gain amplifier circuit. Thereafter, the low noise amplifier is brought to an operating state to thereby allow execution of a DC offset cancel operation of the final-stage programmable gain amplifier.

Wireless communication semiconductor integrated circuit device and wireless communication system

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.

Semiconductor integrated circuit device

Growing community of inventors

Takasaki, Japan

Ikuya Ono