| 摘要 |
PURPOSE:To improve an input surge pressure tightness of a system by a method wherein an effective channel length of a MOSFET connectd to an external terminal of an IC is made longer than the internal FET. CONSTITUTION:A surge is not applied to a driving FET17 and a drain layer of a logical circuit 40 which are not connected to external terminals, as a result, even if an effective channel length is a short channel having a 2mum or less channels length, a threshold value voltage does not fluctuates. Thus, a higher density is sought. Whereas, an effective channel length of FETs 14, 15 for the load use or the output use which are connected to external terminals and may be applied with a surge, is made to be an effective channel length of 2mum or more and the influence of an input surge is prevented. With this constitution, a MOSIC of high density having a sufficient pressure tightness against a surge voltage is obtained, thus reliability being high. |
