| 摘要 |
<p>PURPOSE:To make unnecessary to increase a manufacturing process and to secure a large space, and to obtain a ROM having a high reliability, by constituting a high voltage applied part of a P channel type FET. CONSTITUTION:A high voltage applied part 22 having a P channel type FET Q25 in which a control signal C22 is applied to the gate and a P channel type FET Q24 in which a constant-voltage V0 is applied to the gate is provided in series between a selecting gate line X2 and a write voltage VPP line. The signal C22 becomes a VPP level except the time of a write operation, the Q25 becomes off, and an influence from the VPP line to the line X2 is cut off. Also, at the time of write, the signal C22 becomes a ground level, the Q25 becomes on, and if a decoder output D21 is a ground level, the Q22 becomes off, the selecting line X2 rises to the vicinity of the VPP level, and when a high voltage is applied to a digit lie, a cell M21 becomes a write operation state.</p> |
