| 摘要 |
PURPOSE:To change an input threshold level by connecting one conduction type transistor (TR) of a CMOS inverter in parallel and controlling one of TRs in conductive/nonconductive from an external terminal. CONSTITUTION:In setting a control terminal 2 to a low level, an N-channel MOS TR 8 is always nonconductive and the input buffer uses a P-channel MOS TR 5 and an N-channel MOS TR 7 to constitute the CMOS inverter. In setting the control terminal 2 at a high level, the N-channel MOS TR 8 is always conductive, and the input buffer circuit constitutes the inverter by the P-channel MOS TR 5 and MOS TRs 6, 7, 8. Thus, in setting the control terminal 2 being an external terminal to a low level, the input threshold voltage is brought into a CMOS level and in setting the terminal to a high level, the threshold voltage is brought into a TTL level. |
