| 摘要 |
PURPOSE:To shut out the electric noise generating between a digital circuit part and an analog circuit part by a method wherein a C-MOS integrated circuit is composed of the digital circuit part formed on a one-conductive type semiconductor substrate, and the isolation part having the reverse conductive type diffusion layer to be used for isolation of the circuit parts formed between analog circuit parts and an electrode to be connected to said diffusion layer. CONSTITUTION:The isolated part consisting of a P-well 2', a P type diffusion layer 4' and an electrode 6 is formed between the digital circuit part 10 and the analog circuit part 20. When a C-MOS integrated circuit is going to be used, the lowest potential to be used on the C-MOS integrated circuit is given to the electrode 6. If the electric noise generated on the digital circuit 10 is composed of a positive charge, it is absorbed by the P-well 2' and brought to outside by the electrode 6'. Also, if the electric noise is composed of a negative charge, it is repulsed by the depletion layer which will be formed in the vicinity of the P-well 2', and it cannot reach the analog circuit part 20. |
