JPS5995709A - Microwave semiconductor device - Google Patents

Abstract

PURPOSE:To decrease the loss by providing a circuit biasing a drain of a GaAsFET whose source is grounded by a prescribed voltage and a circuit biasing the gate of the FET by a prescribed voltage so as to operate the FET by a voltage of a single polarity. CONSTITUTION:A bias is impressed to the drain of the GaAsFET5 via a choke 1 from a positive power supply 3, the source is grounded and a bias is impressed to the gate from a positive power supply 7 via a choke 2. As the bias from the power supply 7, a voltage (<=nearly 0.7V) below a forward leading voltage is impressed to the gate of the GaAsFET 5. When a voltage over it is impressed, a current flows to the source from the gate of the GaAsFET, thereby causing increase in noise and deterioration in the GaAsFET. Since a positive voltage only is applied to the GaAsFET as the bias and no resistor is required for the source, the loss due to the resistance is not produced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a microphone Iff wave semiconductor device using U 21 A S F' E '1''.

In recent years, n-channel GaASF'B'l', which has good performance in the microwave band, has been developed and has come to be widely used. n-channel G aA SFE'
1' (hereinafter referred to as GaA 3 F E'l') is the first
As shown in the circuit diagram of figure (a), Gak SF ET
A voltage from the positive power supply 3 is applied to the drain of 5 through the choke 1 (drain bias), and the source is grounded.
A voltage from a negative power supply lO is applied to the gate via the choke 2 (gate bias). These drain bias and gate bias are discharged by a capacitor 4 so that no voltage is applied to the outside. In this way, u;3AB
The k''ET bias voltage requires both a positive voltage power source and a lower voltage power source, which has the drawback of complicating the circuit configuration.

On the other hand, as shown in Figure @1 (b), GaAsFET 5 (7
) There is a bias application method in which a drain bias from a positive power supply 3 is applied to the drain via the choke 1, the gate is grounded via the choke 2, and the source is grounded via the source resistor 6. However, although this method requires only a positive bias voltage, the loss increases because the source resistor 6 is included in the source, and GaAs SFET is used as an amplifier.
When using L, it operates only with gain and has no loss.
It is an object of the present invention to provide a microwave semiconductor device having an rBASFET bias supply circuit.

The microwave semiconductor device of the present invention comprises a A 3 F ET whose gate is grounded, a circuit which biases the drain of this i='E'1' by a given pressure, and the B'
and a circuit that biases the gate of E'l' with the voltage.

The present invention will be explained in detail below using the drawings.

FIG. 2 is a circuit diagram of an embodiment of the present invention. That is, U
aAsl'ET51d A bias is applied to the drain from the positive power supply 3 through the choke 1, and the source is grounded.
A bias from a positive power supply 7 is applied to the gate via a choke 2. The bias from this power supply 7 is G, lAs
A voltage (approximately 0.7 V or less) lower than the rising voltage in the 111-member direction of the gate of 1+'ET5 is applied. If a voltage higher than this is applied, current will flow to the gate and source of GBA Sk' E 'l', increasing noise and (iaA3FE
Deterioration of T @ftj.

FIG. 3 is a circuit diagram of another embodiment of the present invention.

A drain bias is applied to the drain of the UaAsFE'l'5 from the positive voltage source 3 through the choke l, the source is grounded, and the gate bias is supplied from the positive power source 3 through the V leader resistor 8, and the choke 2. Grounded via gate resistor 9. That is, a positive voltage t#3 is applied to the gate, which is the voltage division ratio of the leader resistance and the gate resistance.

As explained in detail above, according to the present invention, GBA 3F
The ET bias can be supplied with only a positive voltage, and since there is no need to insert a resistor into the source, there is no loss due to the resistor.

Note that this microwave semiconductor device operates in class A'.
Suitable for power amplifiers, especially for consumer equipment circuits that require less power.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing a conventional bias application method for a GBA 5 FET, and FIGS. 2 and 3 are circuit diagrams of first and second embodiments of the present invention. In the diagram, 1t2...Choke, 3t7...
...Positive power supply, 4...Capacitor, 5...
...GaA3F E'I', 6... Source resistance, 8... Leader resistance, 9... - resistance, 10... Negative center source. .

Claims (1)

[Claims] G, IA4 k' ET with the source grounded, and this l=
A microwave semiconductor device including a circuit that biases the drain of the 'ET with a voltage of one polarity, and a circuit that biases the gate of the l''ET with the voltage.