JP2003283263A - High frequency amplifier - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase the yield of an integrating circuit provided in a high frequency amplifier 21 for use as a low noise amplifier (LNA) built in the front end of a high frequency receiver circuit, with a low cost. <P>SOLUTION: When an integrating circuit is built in, the inductance value of a negative feedback inductance element varies from its designed value due to variations, parasitic components, etc., in manufacturing steps. To avoid this, a plurality of inductance elements L1 and L2 are provided so that, on the basis of the measured result of an amplification characteristic after packaged, one of the elements is selected to be connected to a high frequency amplifying transistor Q. Accordingly, a reduction in the gain of an LNA caused by the variations and deterioration in the linearity can be corrected, increasing a yield and lowering a cost. Further, when compared with a circuit arranged so that a single impedance element is divided into multiple stages to short-circuit between the stages, this circuit can simplify its arrangement and also reduce its parasitic capacity. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency amplifier circuit used in a front end portion of a receiver circuit which is particularly effective in a microwave range.

[0002]

2. Description of the Related Art A low noise amplifier circuit (LNA) incorporated in a front end portion of a receiving circuit for receiving high frequency signals such as microwaves is used when an unwanted wave defined by intermodulation characteristics or adjacent channel selectivity exists. Moreover, it must have excellent linearity in order to meet the bit error rate of the received data defined by the system. Therefore, as a method for improving the linearity, an LNA having a configuration in which the emitter of a high frequency amplification transistor is grounded via an inductor element is widely used. In this case, the inductor element operates as a negative feedback inductor.

FIGS. 6 and 7 are equivalent circuit diagrams of typical prior art high frequency amplifier circuits 1 and 11. The high-frequency amplifier circuit 1 of FIG. 6 is a single-emitter grounded amplifier circuit. One end of the inductor element l is connected to the emitter of the amplifying transistor q and the other end of the inductor element l is grounded. The base of the amplifying transistor q serves as an input terminal, the collector serves as an output terminal, and is connected to a constant potential point via a load element zl.

The high-frequency amplifier circuit 11 shown in FIG. 7 is a grounded-emitter differential amplifier circuit, and one ends of the inductor elements l1 and l2 respectively corresponding to the emitters of the transistors q1 and q2 forming a differential pair are connected to each other. The other ends of the inductor elements 11 and 12 are grounded. The bases of the transistors q1 and q2 are the input ends of the differential signal, the collectors are the output ends of the differential signal, and they are connected to the constant potential point via the load elements zl1 and zl2, respectively.

A high frequency amplifier circuit 1 having the above-mentioned configuration
In 11, the inductance value of the negative feedback inductor generally has a larger linearity and a better input / output matching although the gain of the amplifier circuit decreases as the inductance value increases up to a predetermined value. That is, the gain and linearity of the amplifier circuit change depending on the inductance value of the negative feedback inductor. However, when the inductor element is incorporated in an integrated circuit, the inductance value varies from the design value due to variations in manufacturing process, parasitic capacitance, and the like. Furthermore, the characteristics of the circuit including these inductor elements may vary greatly from the design value due to the addition of variations in the circuit portion other than the inductor elements. There is a problem in that the yield of the integrated circuit is lowered and the cost is increased due to the reduction of the gain of the LNA and the deterioration of the linearity due to this variation.

Therefore, as another conventional technique capable of solving such a problem, for example, Japanese Patent Application Laid-Open No. 8-162.
No. 331 publication is cited. In this conventional technique, considering the variation of the inductor value of the spiral inductor,
A configuration has been proposed in which the inductance value of the spiral inductor is variable.

[0007]

However, in the above-mentioned prior art, in order to draw out the end portion on the inner peripheral side of the spiral inductor to the outer peripheral side, it is provided on the lower layer side of the spiral conductor via the insulating film. The conductor for drawing out is provided with a switch that short-circuits between the spiral conductor,
The desired inductance value is obtained depending on which switch is used for the short circuit. That is, a single inductor element is divided into multiple stages and each stage is short-circuited.

Therefore, there is a problem that the structure is complicated and the parasitic capacitance component is likely to increase.

An object of the present invention is to provide a high frequency amplifier circuit which can realize the adjustment of the inductance value with a simple structure and without increasing the parasitic capacitance.

[0010]

A high frequency amplifier circuit according to the present invention has at least one stage amplifying transistor and a corresponding negative feedback inductor element, and is a high frequency amplifier circuit mounted on an integrated circuit, wherein: A plurality of inductor elements are provided, switching means for selectively selecting the plurality of inductor elements and connecting to the transistor, and a control value according to a measurement result of the amplification characteristic of the integrated circuit after packaging is set, And a control means for controlling the switching means according to the control value.

According to the above configuration, a low noise amplifier circuit (LNA) incorporated in the front end of the high frequency receiving circuit.
In a high-frequency amplifier circuit used as, for example, when the high-frequency amplifier circuit is built in an integrated circuit, the inductance value of the inductor element for negative feedback varies from the design value due to variations in manufacturing process, parasitic components, etc. It will change. Therefore, by providing a plurality of the inductor elements and selectively selecting the plurality of inductor elements by the switching means and connecting the inductor elements to the transistor, it is possible to compensate for the variation in the inductance value. Configure an amplifier circuit. Then, as the control value for controlling the switching state of the switching means, a value corresponding to the result of measuring the amplification characteristic after packaging the integrated circuit is set.

Therefore, the inductance value of the inductor element can be adjusted after the packaging, and the variation from the design value can be compensated together with the variation in the circuit portion other than the inductor element. As a result, it is possible to correct the decrease in the gain of the LNA and the deterioration of the linearity due to the variation, improve the yield of the integrated circuit, and reduce the cost.

Further, one of the plurality of inductor elements is connected to the MO
Since it is only selected by a switching means such as an S-transistor, a single inductor element is divided into multiple stages and the parasitic capacitance related to the inductor element is simpler than that of a configuration in which each stage is short-circuited. Can also be smaller.

The structure of the high frequency amplifier circuit is as follows.
For example, in a single-emitter grounded amplification circuit, this can be realized by selectively connecting one end of the plurality of inductor elements to the emitter of the amplification transistor and grounding the other end. In the circuit
This can be realized by selectively connecting one end of the plurality of inductor elements in common to the emitters of the transistors forming the differential pair and grounding the other end, and further, the base of the amplifying transistor is an input terminal. , With the collector as the output terminal, applying a bias voltage to the base,
It can be realized by connecting the collector to a constant potential point via a load element, selectively connecting one end of the plurality of inductor elements to the emitter, and grounding the other end.

Further, in the high frequency amplifier circuit of the present invention, each of the plurality of inductor elements is a bonding wire for connecting between the integrated circuit chip and the lead frame.

According to the above-mentioned structure, as the inductor element, the common lead frame is connected to the pads by hitting different numbers of bonding wires from the pads selectively used by the switching means. It is possible to change the inductance value by providing ones having different inductance values from the lead frame and allowing the control means from the outside to select one of the pads to which the emitter of the amplifying transistor is connected. it can.

Therefore, since the spiral inductor is not used, the circuit area can be reduced.

Furthermore, the high frequency amplifier circuit of the present invention is
In a high-frequency amplifier circuit having at least one-stage amplifying transistor and an inductor element for negative feedback corresponding thereto, a single spiral inductor connected to the transistor is provided as the inductor element, Switching means capable of short-circuiting the outermost peripheral portions of the spiral inductor with each other, and a control value according to a measurement result of the amplification characteristic of the integrated circuit after packaging are set, and the switching means according to the control value. And control means for controlling.

According to the above configuration, in the high frequency amplifier circuit used as an LNA incorporated in the front end of the high frequency receiver circuit, a single spiral inductor is provided as the inductor element, and the spiral inductor is switched by the switching means. By switching whether or not the outermost peripheral portions are short-circuited with each other, a variable-gain high-frequency amplifier circuit capable of compensating for variations in inductance value is configured. Then, as the control value for controlling the switching state of the switching means, a value corresponding to the result of measuring the amplification characteristic after packaging the integrated circuit is set.

Therefore, the inductance value of the inductor element can be adjusted after the packaging, and the variation from the design value can be compensated together with the variation in the circuit portion other than the inductor element. As a result, it is possible to correct the decrease in the gain of the LNA and the deterioration of the linearity due to the variation, improve the yield of the integrated circuit, and reduce the cost.

Further, by using a spiral inductor formed on the integrated circuit as the inductor element, the variable gain high frequency amplifier circuit can be completely integrated in the integrated circuit, and the switching means is a spiral inductor. Since it is simply switched whether or not the outermost peripheral portions of the inductors are short-circuited with each other, the parasitic capacitance related to the inductor element can be reduced with a simple structure.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding one embodiment of the present invention,
The following is a description with reference to FIGS. 1 to 4.

FIG. 1 is an equivalent circuit diagram of a high frequency amplifier circuit 21 according to an embodiment of the present invention. This high frequency amplifier circuit 1
Is a single-emitter grounded amplification circuit, one end of the inductor element L1 or L2 is selectively connected to the emitter of the amplification transistor Q by the switching circuit 22, and the other ends of the inductor elements L1 and L2 are both grounded. To be done. The base of the amplifying transistor Q serves as an input terminal and the collector serves as an output terminal, and is connected to a constant potential point via a load element ZL. The inductance values of the inductor elements L1 and L2 are different from each other, and three or more inductor elements may be provided. The switching circuit 22 is switching-controlled according to the control value set in the control circuit 23.

FIG. 2 is a block diagram showing a configuration example of the switching circuit 22 and the control circuit 23.

The switching circuit 22 comprises two MOS transistors M1 and M2 and an inverting circuit NOT. The MOS transistors M1 and M2 include
The size is selected so that the on-resistance and parasitic capacitance components do not affect the circuit operation. These MOS transistors M1 and M are connected to a terminal P0 which is connected to the emitter of the amplifying transistor Q and serves as a common contact of the switching circuit 22.
The two sources are connected together, and the drains are connected to the inductor elements L1 and L2, respectively, and to the terminals P1 and P2 that are individual contacts of the switching circuit 22, respectively. MOS
The output of the control circuit 23 is directly applied to the base of the transistor M1, and the output of the control circuit 23 is supplied to the base of the MOS transistor M2.
Given after being flipped at.

On the other hand, the control circuit 23 provided outside the integrated circuit supplies the switching circuit 22 with the reference voltage or the ground potential from the bias power source B by the switch S. The state of the switch S corresponds to the result of actually measuring the amplification characteristic after the packaging of the high frequency amplification circuit 21 and determining which of the inductor elements L1 and L2 should be selected.

In the measurement, the switch S is switched to a predetermined potential side, that is, a predetermined one of the inductor elements L1 and L2 is selected,
This is performed by inputting a high frequency signal to be amplified into the base of the amplifying transistor Q and measuring the output from the collector. The switching state of the switch S is set according to the measurement result.

Therefore, when the switch S of the control circuit 23 outputs the ground potential, the MOS transistor M1 is turned on and the MOS transistor M2 is turned off, and the inductor element L1 is connected to the emitter of the amplification transistor Q.
When the potential is output from the bias power source B, the MOS transistor M2 becomes conductive, the MOS transistor M1 is cut off, and the inductor element L2 is connected to the emitter of the amplifying transistor Q.

Thus, the inductor elements L1 and L2 are
Is selectively connected to the emitter of the amplifying transistor Q, and when the inductance value increases, the gain decreases,
The linearity is improved, and conversely, when the inductance value is decreased, the gain is increased and the linearity is deteriorated. By selecting the inductor elements L1 and L2 in this way, it is possible to compensate for the variation from the design value together with the variation of the circuit portion other than the inductor elements L1 and L2. As a result, it is possible to correct the decrease in the gain of the LNA and the deterioration of the linearity due to the variation, improve the yield of the integrated circuit, and reduce the cost.

Further, one of the plurality of inductor elements L1 and L2 is connected to the switching circuit 22 of the MOS transistors M1 and M2.
It is possible to reduce the parasitic capacitance related to the inductor element with a simple structure as compared with a configuration in which a single inductor element is divided into multiple stages and each stage is short-circuited. .

FIG. 3 is a perspective view showing a specific structural example of the inductor elements L1 and L2. In this example, bonding wires 24 are used for the inductor elements L1 and L2. From the respective pads of the integrated circuit chip 25 corresponding to the terminals P1 and P2, wire bonding is performed on the inner leads IL serving as ground terminals in different numbers (in FIG. 3, the terminal P1 side is 2).
Book, one on the terminal P2 side).

Therefore, the inductance value can be switched by selecting which pad the emitter of the amplifying transistor Q is connected to by the switching circuit 22. Thus, the circuit area can be reduced without using the spiral inductor.

FIG. 4 shows an example in which the same configuration is applied to a grounded-emitter differential amplifier circuit. In the high frequency amplifier circuit 31, the transistors Q1 and Q2 forming a differential pair are included.
One end of the inductor element L11, L21 or L12, L22 is selectively connected to the emitter of the inductor element L11, L21 by the switching circuit 32.
1; The other ends of L12 and L22 are both grounded. The bases of the amplifying transistors Q1 and Q2 are the input ends of the differential signal, the collectors are the output ends of the differential signal, and they are connected to the constant potential point via the load elements ZL1 and ZL2, respectively. There is. The inductor element L11
And L12, and the inductor elements L21 and L22 have mutually different inductance values, and three or more inductor elements may be provided for each of the amplifying transistors Q1 and Q2. The switching circuit 32 is switching-controlled according to the control value set in the control circuit 23.

Another embodiment of the present invention will be described below with reference to FIG.

FIG. 5 is a front view showing the structure of an inductor element L according to another embodiment of the present invention. It should be noted that
The inductor element L is composed of a single spiral inductor integrally formed in the integrated circuit, and has an outermost peripheral portion L.
That is, whether or not O is short-circuited with each other is switched by the switching circuit 42 controlled by the control circuit 23.

That is, the inductor element L has a terminal A1 on the outermost peripheral side, and a terminal A2 is provided on the inner peripheral side of the spiral inductor approximately one round from the position of the terminal A1. , A2, the switching circuit 42 is interposed. Further, the innermost peripheral side of the spiral inductor is a terminal B which is drawn out to the outermost peripheral side by traversing each conductor of the spiral inductor formed in a spiral shape through an insulating layer (not shown). And
One of the terminals A1 and B is connected to the emitters of the amplification transistors Q; Q1 and Q2, and the other is grounded.

By configuring the inductor element L in this way, it is only necessary to switch whether or not the outermost peripheral portions LO are short-circuited with each other, so that the parasitic capacitance related to the inductor element L can be reduced with a simple structure. be able to.
Also, the circuit area can be reduced.

Here, in the above-mentioned Japanese Patent Laid-Open No. 8-162331, a switch which short-circuits the spiral-shaped conductors indicated by reference numeral D in FIG. And a desired inductance value is obtained depending on which switch is used for short-circuiting.
That is, since a single inductor element is divided into multiple stages and each stage is short-circuited, the structure is complicated and the parasitic capacitance component is further increased.

By the way, although the high frequency amplifying transistors Q; Q1 and Q2 have been described as bipolar transistors, it goes without saying that they may be MOS transistors.

[0040]

As described above, the high-frequency amplifier circuit of the present invention is a high-frequency amplifier circuit used as a low noise amplifier circuit (LNA) incorporated in the front end of a high-frequency receiver circuit. If incorporated in, the inductance value of the inductor element for negative feedback will vary from the design value due to variations in the manufacturing process and parasitic components, and gain and linearity will change.
A plurality of the inductor elements are provided, and the inductor elements are selectively selected according to the result of measuring the amplification characteristic after packaging of the integrated circuit and connected to the high frequency amplification transistor.

Therefore, the inductance value of the inductor element can be adjusted after the packaging, and the variation from the design value can be compensated together with the variation in the circuit portion other than the inductor element. As a result, it is possible to correct the decrease in the gain of the LNA and the deterioration of the linearity due to the variation, improve the yield of the integrated circuit, and reduce the cost.

Further, one of the plurality of inductor elements is MO
Since it is only selected by a switching means such as an S-transistor, a single inductor element is divided into multiple stages and the parasitic capacitance related to the inductor element is simpler than that of a configuration in which each stage is short-circuited. Can also be smaller.

Further, in the high frequency amplifier circuit of the present invention, as described above, each of the plurality of inductor elements is used as a bonding wire, and a common lead frame is provided with a different number of bondings from the pads that are selectively used. By providing a wire or the like, those having different inductance values between the pad and the lead frame are provided.

Therefore, since the spiral inductor is not used, the circuit area can be reduced.

Furthermore, the high frequency amplifier circuit of the present invention is
As described above, in a high-frequency amplifier circuit used as an LNA incorporated in the front end of a high-frequency receiver circuit, a single spiral inductor is provided as an inductor element, and the amplification characteristic is measured according to the result of measurement after packaging the integrated circuit. , It is switched whether or not the outermost peripheral portions of the spiral inductor are mutually short-circuited.

Therefore, the inductance value of the inductor element can be adjusted after the packaging, and the variation from the design value can be compensated together with the variation in the circuit portion other than the inductor element. by this,
It is possible to correct the decrease in the gain of the LNA and the deterioration of the linearity due to the variation, and improve the yield of the integrated circuit.
The cost can be reduced.

Further, by using the spiral inductor formed on the integrated circuit as the inductor element, the high frequency amplifier circuit of variable gain can be completely integrated in the integrated circuit, and the switching means is the maximum of the spiral inductor. Since it is merely switched whether or not the outer peripheral portions are short-circuited with each other, the parasitic capacitance related to the inductor element can be reduced with a simple structure.

[Brief description of drawings]

FIG. 1 is an equivalent circuit diagram of a high-frequency amplifier circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration example of a switching circuit and a control circuit in the high frequency amplifier circuit shown in FIG.

3 is a perspective view showing a specific configuration example of an inductor element in the high-frequency amplifier circuit shown in FIG.

FIG. 4 is an equivalent circuit diagram of another example of the high-frequency amplifier circuit according to the embodiment of the present invention.

FIG. 5 is a front view showing a configuration of an inductor element according to another embodiment of the present invention.

FIG. 6 is an equivalent circuit diagram of a typical prior art high frequency amplifier circuit.

FIG. 7 is an equivalent circuit diagram of a typical prior art high frequency amplifier circuit.

[Explanation of symbols]

21, 31 High-frequency amplifier circuits 22, 32, 42 Switching circuit 23 Control circuit 24 Bonding wire 25 Integrated circuit chip B Bias power supply IL Inner leads L; L1, L2; L11, L12, L21, L22
Inductor element LO Outermost portion M1, M2 MOS transistor NOT Inversion circuit Q Amplification width transistor Q1, Q2 Transistor S switch ZL; ZL1, ZL2 Load element

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5J092 AA04 AA51 CA87 CA91 CA92                       CA98 FA18 HA02 HA10 HA33                       HA38 HA39 KA04 MA11 QA03                       QA04 SA13                 5J500 AA04 AA51 AC87 AC91 AC92                       AC98 AF18 AH02 AH10 AH33                       AH38 AH39 AK04 AM11 AQ03                       AQ04 AS13

Claims (3)

[Claims] 1. A high-frequency amplifier circuit having at least one-stage amplifying transistor and a negative feedback inductor element corresponding to the amplifying transistor, wherein the inductor element is provided in a plurality, and the plurality of inductor elements are provided. Switching means that is alternatively selected and connected to the transistor, and a control value according to a measurement result of the amplification characteristic of the integrated circuit after packaging is set, and the switching means is controlled according to the control value. A high-frequency amplifier circuit including control means. 2. The high frequency amplifier circuit according to claim 1, wherein each of the plurality of inductor elements is a bonding wire connecting between the integrated circuit chip and the lead frame. 3. A high-frequency amplifier circuit having at least one-stage amplifying transistor and a negative feedback inductor element corresponding to the amplifying transistor, and a single high-frequency amplifier circuit connected to the transistor as the inductor element. A switching means that is provided with a spiral inductor and is capable of short-circuiting the outermost peripheral portions of the spiral inductor to each other, and a control value according to the measurement result of the amplification characteristic of the integrated circuit after packaging is set, A high-frequency amplifier circuit including control means for controlling the switching means in response thereto.