| 摘要 |
<p>PURPOSE:To improve action speed by inserting a level down transistor into a precharge circuit. CONSTITUTION:The transistor 13 is inserted into the precharge level circuit, and the fall of potential due to the threshold value of the transistor is utilized. The number of circuits to be serially connected to othe transistor 13 is decided in light of a using voltage, the threshold voltage of each transistor, an action voltage margin, etc. For the power source of an initial inverter receiving a ROM output signal, the level of a line 14 subjected to level-down is used. By applying these circuits, a power source voltage margin is expanded up to the voltage range of a normal CMOS circuit. If the conductance ratio to PMOS/ NMOS of an inverter 10 acting as a sense circuit by raising the threshold value is made higher, the action speed can be higher without affecting adversely a voltage margin.</p> |
