| 摘要 |
PURPOSE:To prevent a hole from being injected into a substrate by providing a clamping transistor (TR) to the data output stage of a semiconductor memory, and clamping noises applied form an output terminal and holding a negative voltage applied to a substrate stably. CONSTITUTION:The output stage consisting of a load TR Q1 and a driver TR Q2 is provided with the clamping TR Q3. The threshold voltage VTH of The TR Q3 is lower than the forward voltage VF of p-n junction. If a noise higher than VCC+VF is applied to the output terminal D, the TR Q3 clamps the level at the terminal DO to VCC+VTH. Consequently, the p-n junction is prevented from becoming forward, the negative voltage VBB applied to a (p)-type semiconductor substrate is held stable, and a hole is prevented from being injected into the substrate. |
