| 摘要 |
PROBLEM TO BE SOLVED: To arrange a constitution, such that a low noise-resistant circuit is hard to be influenced by the noise generated in a logical circuit and by interface buffer circuit made on the same semiconductor substrate. SOLUTION: Since a low noise-resistant circuit 108 is arranged at the corner 6 of a semiconductor substrate 104, the low noise-resistant circuit 108 is not surrounded by noise sources, unlike the case of a conventional semiconductor integrated circuit, and even if the noise is transmitted to the low noise-resistant circuit 108 through the semiconductor substrate 104, the noise is only from the inward direction of the semiconductor substrate 104, and the quantity of the noise transmitted to he low noise-resistant circuit 108 decreases sharply. Moreover, a lightly-doped region 12, which partitions the low noise-resistant circuit 108 off a logical circuit and an interface buffer circuit, is made at the boundary inside the corner region 6, and this region is low in impurity concentration, and is high in impedance. For this reason, the noise transmitted to the low noise-resistant circuit 108 is attenuated sharply while it passes this region.
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