| 摘要 |
PURPOSE:To improve a crosstalk characteristic in case when a signal is cut off and also power consumption in that case, by using a field effect transistor in a wide band emitter-follower type switching circuit of or a switching circuit using a diode. CONSTITUTION:When a controlling transistor 5 is turned on by controlling a base current of the transistor 5 by the potential of a control terminal 6, a current flows to a resistance 9, and the gate-source voltage of a field effect transistor (FET) 15 is set to reverse bias voltage by a voltage drop generated in the resistance 9. Accordingly, the FET15 becomes a cut-off state, and the current flowing in the resistance 9 becomes a bias current of the emitter of a transistor (TR) 3 and the base of a TR4. As a result, emitter-follower circuits of 2 stages are operated, and a signal is outputted to an output terminal 2. When the TR5 is turned off from the control terminal 6, the FET15 attains to a conducting state, the potential of a connecting point 10 attains the same potential as that of an electric power source terminal 7, and the base-emitter potential of the TR3 and 4 is biased in the reverse direction. Also, the connecting point 10 is grounded in AC. |
