| 摘要 |
PURPOSE:To prevent input terminals of a semiconductor device from being damaged due to an external surge with power source terminals in an open state by disposing one end of a diffused layer connected with a first input terminal and one end of a diffused layer connected with second and third input terminals disposed adjacently in parallel at a predetermined distance and separating the diffused layers connected with the input terminals from input/output protecting circuits. CONSTITUTION:Diffused layers 9b connected with terminals 1b are provided at both ends of an input terminal 1b, and are spaced at a predetermined distance from diffused layers 9a, 9c connected with input terminals 1a, 1c disposed adjacent to the terminal 1b. Accordingly, a surge is applied to the layer 9bs of both ends of a diffused protecting resistor 4b connected with the terminal 1b and the terminal 1b at the moment that an external surge is applied between the input terminals with power source terminal in a floating state, and a surge to an input transistor is delayed in the amount due to the parasitic capacity and the resistance of the resistor 4b. The depletion layer of the layer 9b arrives at the layers 9a, 9b within the delayed time, the surge flows to the terminals 1a, 1c to alleviate an electric field intensity applied to the input transistor, thereby preventing a gate oxide film from being damaged. |
