| 摘要 |
PURPOSE:To input a signal to an external signal terminal and to arbitrarily set an input level by providing a P channel type MOS transistor respectively between a power source terminal and an input terminal, and also an output terminal. CONSTITUTION:When '0'V is impressed to a control terminal, a P channel type MOS transistor 11 is energized, the ratio of a channel width goes to a first value and an inverter 14 goes to the input circuit of a CMOS level. When a prescribed voltage is impressed to a control terminal, an N channel type MOS transistor 11 goes to the non-energized state, and the P channel type MOS transistor 10 goes to the non-energized state while the gate is clamped by a resistance 12. In such a case, the ratio of the cannel width goes to a second value and the inverter 14 goes to the input circuit of a TTL level.
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