| 摘要 |
PURPOSE:To obtain an inverting voltage whose operating level is identified accurately even when the effect of leakage or substrate is caused by setting a ratio of sizes of a P-channel MOS transistor (TR) and an N-channel MOS TR of a detection inverter detecting the output voltage of a ROM cell to nearly 1:5-1:20. CONSTITUTION:An inverter consists of a P-channel MOS TR Q1 connected to a power supply VDD and an N-channel MOS TR Q2 connected to ground, gates and drains are connected in common to be an input terminal and an output terminal respectively. In this case, the ratio of the size of the P-channel MOS TR Q1 and the N-channel MOS TR Q2 is set to nearly 1:5-1:20. Thus, an inverted voltage Vth2 able to identify the logic level accurately is obtained. |
