| 摘要 |
PURPOSE:To obtain an input protecting circuit which can be integrated and accelerated by forming a protective diode of P type impurity region and a high density N type first impurity region with N type well as a protecting resistor. CONSTITUTION:An N type well region 32 is formed in a P type semiconductor substrate 31 set to ground potential, and a P+ type impurity region 33 which is higher density than the substrate 31 is formed and grounded in the region 32. Further, high density N<+> type first impurity region 34 is formed, and connected to the input stage of the internal circuit. Impurity regions 33, 34 and high density N<+> type impurity region 35 are formed at the prescribed interval in the region 32, and connected to an input terminal 11. A diode 36 is formed of a semiconductor substrate 31 and the region 32, and a protective resistor 37 is formed of the region 32, and a diode 38 is formed of P<+> type impurity region 33 and N<+> type impurity region 34. |
