| 摘要 |
PURPOSE:To attain an input level conversion circuit protecting an input gate from a surge and receiving a comparatively large input amplitude by discharging the surge voltage through a P-N junction diode. CONSTITUTION:A current limit element 1 is connected to an input terminal 10 and a node 11, the anode and cathode of the P-N junction diodes 2, 3 are connected to a power terminal respectively and the cathode and anode are connected respectively to the node 11. The drain of an enhancement GaAs MESFET is connected to a power terminal 100, a gate is connected to the node 11 and a source is connected to a node 12. If a surge enters the input, a current is conducted from the input to a power supply from the diode 3 in the case of a positive surge and the current is conducted from a power supply to the input by the diode 2 to protect the gate of the FET 4. Since the P-N diodes are used for the diodes 2, 3, the input amplitude is increased by the barrier voltage of the diodes. |
