| 摘要 |
PURPOSE:To generate sufficiently high output potential and shorten the output transition time by separating the P well of a pull-up drive comprising an NMOS type transistor from the other P well and connecting a back gate to a source. CONSTITUTION:An output buffer separates a P well 9a, in which an NMOS type transistor Q1 for a pull-up driver is formed, from the other P well 9 and connects the back gate thereof, or said P well 9a, to the source 4 thereof, or an output terminal 1. Therefore, no back gate effect on the NMOS type transistor Q1 for a pull-up driver is produced, so that the threshold voltage does not increase even in increase of output potential. Thereby sufficiently high output potential can be generated and the drive ability decreases less. |
