JP2738701B2 - High frequency amplifier circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-frequency amplifier circuit, and more particularly, to an amplifier using a semiconductor element in a high-frequency region, and particularly to a circuit configuration suitable for high efficiency.

[Conventional technology]

Conventionally, on the output side as a means of increasing the efficiency of a high-frequency amplifier,
It is known to provide a circuit that takes into account harmonic impedance. For example, microwave research group materials (MW83-
According to 24), if the output impedance is set to zero for even-order harmonics and to infinity for odd-order harmonics, theoretically nearly 100% efficiency can be obtained. In addition, an example using a distributed constant line as a specific circuit configuration is described.

[Problems to be solved by the invention]

In the prior art, since the output impedance is configured using a strip line or a coaxial line which is a distributed constant line, the output impedance becomes large when the frequency is relatively low (for example, 1/4 wavelength 7.5 cm at 1 GHz). That the output end of the element does not become zero due to the bonding line to the output end of the element, etc.It is necessary to configure a circuit at a position relatively distant from the element to be made zero at the output end of the element. Loss reduces efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to realize a high-efficiency high-frequency amplifier circuit with a small size and zero impedance with respect to a double harmonic at the element output terminal.

[Means for solving the problem]

The above object is to provide a series circuit of inductance and capacitance by a lumped constant in parallel with an output line at the output end of the element, ground one end of the series circuit, and make the inductance and capacitance values twice the operating frequency. This is achieved by setting a value that causes series resonance at a frequency. For example, using a bonding line from the output end of the element as inductance by lumped constant and using a chip capacitor as capacitance, the operating frequency
Considering the case of 1GHz, it is about 2nH at 25μmφ 2mm long,
With ε = 100, thickness 0.5 mm, and area 1.5 mm ² , it becomes about 3 pF, and this series circuit is short-circuited at 2 GHz which is twice the frequency.

That is, the circuit for the above purpose can be realized with an extremely small area of the element frequency mm. On the other hand, if this is configured with a distributed constant circuit, the length of the quarter-wave stub of 2 GHz becomes as large as about 15 mm on a commonly used alumina substrate, and the short-circuit condition at the element output end is affected by the effect of the bonding line. Requires complex circuits.

[Action]

The operation of the present invention will be described with reference to FIG. Reference numeral 1 denotes a field effect transistor (FET) which operates as a source ground. Inductance L ₂ and Kiyapashitansu C ₂ are connected in series between the drain terminal and the ground as the output terminal of the FET. The value of the L ₂ and C ₂ is _{L 2 · C 2 = (1} / 2π
₂ ) ² , where ₂ is a frequency twice as high as the operating frequency, causes series resonance, and short-circuits to the second harmonic. On the other hand, at the operating frequency, the impedance becomes a certain impedance, and this impedance and the impedance of the FET are connected in parallel. By appropriately setting the values of L ₁ , L ₁ ′, and C ₁ with respect to the total impedance, matching is made with respect to the operating frequency, and the resultant is connected to the output strip line. Note that the lumped constant circuits of L ₁ , L ₁ ′, and C ₁ do not necessarily need to be provided, and the fundamental wave may be matched by a strip line.

〔Example〕

 Hereinafter, the embodiment will be described in detail.

FIG. 2 shows an embodiment of a high-frequency amplifier according to the present invention, in which metal wires 4, 5 are bonded to an output bonding pad 2 of a transistor chip 1, and a capacitor 6 formed of a pad on a dielectric chip 8. , 7.
A metal wire 9 is connected from the chip capacitor 7 to the output strip line 10. In the drawing, 3 is an input bonding pad, 12 is an input side metal wire, and 11 is a dielectric substrate forming an output side strip line. In such a structure, the inductance of the metal wire 4 and the capacitance of the capacitor 6 correspond to L ₂ and C ₂ in the figure, and the length and number of the metal wires 4 and the pad area of the capacitor 6 are adjusted to twice the operating frequency. Is set to cause series resonance at the frequency of

FIG. 3 is a block diagram of another embodiment of the present invention, in which a dielectric chip 8 is provided between a transistor chip 1 and an output strip line 10, and a pad on which a capacitor is formed.
This is the case where 6, 7 are arranged in two rows.

FIGS. 2 and 3 show two dielectric chips on one dielectric chip.
Although a pad for forming the capacitor is provided, it is not always necessary to use one dielectric chip, and two dielectric chips may be used.

FIG. 4 shows another embodiment, in which the matching circuits L ₁ , L ₁ ′ and C ₁ for the operating frequency of FIG. ₁ are not used. That is, one pad 6 forming a capacitor is provided on the dielectric chip 8 provided between the transistor chip 1 and the output strip line 10, and the inductance of the metal wire 4 and the value of the capacitance of the pad 6 are doubled. Set so that series resonance occurs with respect to the frequency.

Figure 5 is a further embodiment, a case of providing on a dielectric substrate constituting the output strips line the Kiyapashita forming a Kiyapashitansu C _2.

FIG. 6 is a block diagram of another embodiment of the present invention, in which a transistor and a circuit are formed on the same substrate, that is,
The output terminal of a transistor (FET
In this case, a spiral inductance and a capacitance are connected to the output strip line 10 in parallel to the drain electrode), and a series resonance is caused by the sum of the inductance of the spiral line 4A and the metal wire 4B and the capacitance of the capacitor 6 '. Set. 13 is an input line on the gate side, and 14 is a source electrode. Although the same circuit is provided on both sides of the output stop line in the figure, it is effective to use only one side.

〔The invention's effect〕

According to the present invention, a circuit which is short-circuited to the second harmonic component at the transistor output terminal effective for improving the efficiency of the amplifier circuit can be realized with a very small area of several mm ^{2, and as} a result, the circuit can be packaged. This makes it possible to realize a package suitable for increasing the efficiency of the transistor, thereby improving the efficiency of the transmission / reception device by using an amplifier, and achieving the miniaturization and high performance of the entire device.

[Brief description of the drawings]

FIG. 1 is a diagram showing an equivalent circuit of the present invention, and FIGS. 2 to 6 are top views of an embodiment of a high-frequency amplifier according to the present invention. 1 ... transistor chip, 2 ... output bonding pad, 3 ... input bonding pad, 4,5 ... metal wire, 6,7 ... capacitor, 8 ... dielectric chip, 9 ...
... Metal wire, 10 ... Strip line for output, 11 ... Dielectric substrate, 12 ... Metal wire on input side, 13 ... Line for input, 14 ...
Source electrode.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-87406 (JP, A) JP-A-62-111 (JP, A) JP-A-55-72324 (JP, U)

Claims (5)

(57) [Claims] A semiconductor device, a first metal wire having one end connected to an output bonding pad of the semiconductor device, and an output strip line connected to the other end of the first metal wire. In the high-frequency amplifier circuit, one end of a series resonance circuit including an inductor and a capacitor is connected to the output bonding pad, the other end of the series resonance circuit is grounded, and the inductance value of the inductor and the capacitance value of the capacitor are provided. Is set to a value that causes series resonance at twice the operating frequency. 2. The method according to claim 1, wherein the capacitor is a first chip capacitor using a dielectric, and the inductor is a second metal line connecting the first chip capacitor and the output bonding pad. The high-frequency amplifier circuit according to claim 1, characterized in that: 3. The high-frequency amplifier circuit according to claim 2, wherein said first chip capacitor is arranged at an intermediate position between said semiconductor element and said output strip line. 4. The high-frequency device according to claim 2, wherein said first chip capacitor is provided on the same dielectric substrate as a dielectric substrate constituting said output strip line. Amplifier circuit. 5. A second chip capacitor using the same dielectric as that of said first chip capacitor is provided, and one end of said second chip capacitor is connected to an intermediate portion of said first metal wire. 3. The second chip capacitor according to claim 2, wherein the other end of said second chip capacitor is grounded, and said first metal wire and said second chip capacitor are matched with respect to an operating frequency. 2. The high-frequency amplifier circuit according to 1.