Semiconductor integrated circuit device and audio appliance employing it

Abstract

A semiconductor integrated circuit device has an analog signal conductor and a digital signal conductor formed on a single circuit board. In the lowest layer is laid a polysilicon conductor as the digital signal conductor, on top thereof is laid a first aluminum conductor as a shielding conductor, and further on top thereof is laid a second aluminum conductor as the analog signal conductor. With this structure, it is possible to give the highest priority to improving the transmission quality of analog signals and simultaneously reduce transfer of noise from the digital signal conductor to the analog signal conductor.

Description

[0001] This application is based on Japanese Patent Application No. 2003-131935 filed on May 9, 2003, the contents of which are incorporated herein by reference. technical field [0002] The present invention relates to a semiconductor integrated circuit device having analog signal conductors and digital signal conductors formed on a single circuit board. The present invention also relates to an audio device using such a semiconductor integrated circuit device. Background technique [0003] In a semiconductor integrated circuit device having analog signal conductors and digital signal conductors formed on a single circuit board, it is necessary to take measures to reduce crosstalk between conductors when designing conductor layouts. In conventional semiconductor integrated circuit devices, a common method to minimize crosstalk is to: (1) minimize the area where two conductors intersect each other (see Figure 3A ), (2) the conductor is detoured so that it does not intersect ...

AI Technical Summary

Problems solved by technology

However, in semiconductor integrated circuit devices such as operational amplifier ICs designed for audio equipment or the like, in which priority is given to improving the transmission quality of analog signals (audio signals) on which playback sound quality depends, and in which digital signals ( For example, the transmission quality and related characteristics of equipment operating signals with a frequency of 1 [MHz] or less are of less importance, and the techniques for resisting crosstalk disclosed in the above publications are not the most suitable

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