Semiconductor device having input protection circuit.

摘要

An input protection circuit is formed on a semiconductor substrate. A double well structure (102, 103) is formed by an impurity diffusion region (104) and a protective circuit region (103) containing the input protection circuit. A first potential setting source (105) is connected to a separation region to set a predetermined potential, and a second potential setting source (VBB) is connected to the semiconductor substrate to set a potential in the semiconductor substrate such that the separation region and the semiconductor substrate are reversely biased. Whereby, the semiconductor substrate including an internal circuit element (160) and a peripheral circuit element is electrically isolated from the double well structure (102, 103).