Oki Electric Industry Co., Ltd.

Oki Semiconductor Co., Ltd.

Kouji Morita

Naoaki Sugimura

Seiichiro Sasaki

Masaru Sekiguchi

A DA converter includes an IV conversion amplifier with output voltage having good linearity, to thus improve total harmonic distortion (THD) characteristics. In the DA converter, a first current path in which current flows due to differential switches being in the ON state in a differential switch section, and a second current path in which current flows due to differential switches being in the OFF state in the differential switch section are connected to the output side of the IV conversion amplifier. A first current flows in the first current path and a second current flows in the second current path. A current equal to the first current plus the second current that is of fixed current amount is drawn by an amplifier stage of the IV conversion amplifier.

DA converter including conversion amplifier having output voltage with improved linearity

The present invention provides a multilayered power supply line suitable for use in a semiconductor integrated circuit and a layout method thereof. In the multilayered power supply line () for the semiconductor integrated circuit, a top metal () and a second metal () are electrically connected to each other by through holes (). Further, a capacitor metal () is electrically connected to the top metal () by through holes () to thereby make the top metal (), the second metal () and the capacitor metal () identical in potential to one another, whereby the multilayered power supply line functions as a power supply line based on normal wiring metals without functioning as a capacitor. It is thus possible to supply power with reduced impedance.

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Saitama, Japan

Kouji Morita