| 摘要 |
<p>PURPOSE:To confirm whether a redundancy function is being used or not easily from the outside by inserting the source or drain terminal of an N channel MOS transistor and a fuse, which is not blown out when the redundancy function is not used and is blown out when it is used, in series between one signal terminal and a supply potential supply terminal. CONSTITUTION:An input protective circuit 12 for removing surge voltage applied from the outside is connected to one signal input terminal 11 in a plurality of signal input terminals transmitting signals over the inside of an IC, and the gate terminal and drain or source terminal of the N channel MOS transistor 13 are connected in common with the output terminal side of the circuit 12. The fuse 15, which is blown out when the redundancy function is used and is not blown out when it is not used, is inserted between the source or drain terminal and a potential point 14 supplied with positive polarity supply potential VDD on operaton. Another N channel element 17 is connected at a series node 16 of the transistor 13 and the fuse 15.</p> |
