JPS61101105A - Radio frequency amplifier - Google Patents

Abstract

PURPOSE:To attain ease of semiconductor circuit integration of an FET circuit part by making each of AGC position input gate of an FET of each RF amplifier series in common in the two series of RF amplifiers using a dual gate FET as an amplifier element. CONSTITUTION:Q, Q formed by a semiconductor integrated circuit are FETs for amplification of, e.g., UHF and VHF bands, the 2nd gates G, G are connected and led to one bonding terminal 41 and an AGC voltage as UHF, VHF band amplifier circuit is given to the terminal via a resistor 42. The selection and switching of the amplifier circuit at the UHF, VHF bands of the circuit are conducted by applying a cut-off voltage to the 1st gates G, G of the signal input gates of each FET.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a radio frequency amplifier monolithically integrated into a semiconductor circuit.

(Conventional structure and its problems) Recently, radio frequency amplifiers (hereinafter referred to as RF
There is an attempt to make an amplifier (amplifier) into a semiconductor integrated circuit.

An example of such an RF unit is a television tuner. TV radio waves are VHF of 50 to 300 MHz.
Since two frequency bands are used: the 'band and the UHF band of 490 to 890 MH2, TV tuners generally have a two-line circuit configuration for each frequency band, and switching between frequency bands is as follows: For example, in a device using FgT as an amplifying element, this is done by controlling the drain voltage with a diode switch. There is also a movement to use a single circuit instead of two circuits, but this cannot satisfy the extremely sophisticated distortion characteristics required for TV tuners, and it is recommended to install RF amplifiers for each of the VHF and UHF bands. is realistic.

FIG. 1 shows the conceptual configuration of the above-mentioned television tuner, in which the outputs of RF amplifiers 7t'1 and 2 provided for UHF and VHF bands, respectively, are transmitted via terminals 3 and 4 to A 5Vc switching input is input to the next stage circuit such as a mixer. In addition, 6.7 is the UI (F-charged radio wave and VH
This is an input terminal for F-charged radio waves.

RF amplifiers 1 and 2 each have a power input terminal 8,
8', AGC input terminals 9, 9', and a switching control input terminal 10 for selectively switching RF amplifier 1 or 2.
, 10'.

A problem in fabricating such a circuit into a monolithic semiconductor integrated circuit is that the number of terminals is large, and this will be explained in detail with reference to FIG.

That is, FIG. 2 shows a specific circuit example of the television tuner conceptually explained in FIG. 1, and now we will consider the case where the area within the dotted line H is monolithically integrated into a semiconductor integrated circuit. GaAs
FET Lf) Q I integrated into an integrated circuit.

Q2 amplifies UHF electromagnetic waves, and <Q3 amplifies VHF electromagnetic waves. U and V are UHF and VHF respectively
are receiving input tuning circuits whose outputs are applied to FETs Ql and Q3 from terminals 21 and 22, respectively.

23.24 is the UHF band AGC voltage input terminal, 25 is V
HF band AGC voltage input terminal, 26&! Output terminal of FET-Ql, 27 is input terminal of FET-Q 2, 28 is the same (power input terminal of FET-Q 2, 29 is UHF amplification output terminal, 30 is common to FET-Q 1 to FET-Q 3) The source terminal 31 is a VHF amplification output terminal.

Resistors, capacitors, choke coils, etc. of the bias circuit indicated by other wiring symbols have large shapes and are not suitable for monolithic integrated circuits, and therefore are externally connected to the circuit.

As can be seen from the above, although the circuit within the dotted line H to be fabricated into a monolithic semiconductor integrated circuit is relatively simple, the required input/output terminals are 21.
As many as 11 locations, from 31 to 31, must be formed.

In the case of a monoline semiconductor integrated circuit, this leads to waste of semiconductor chip area required for bonding and bonding, and must be avoided as much as possible. In fact, in the case of FIG. 2, 40 to 50% of the semiconductor chip area is occupied by the bonding set portion, which is a cause of high cost.

(Object of the Invention) The present invention eliminates the disadvantages of forming the above-mentioned conventional two-system RF amplifier using a monolithic semiconductor integrated circuit, and uses a new circuit configuration that maintains the same circuit function as the conventional one. It is an object of the present invention to provide an RF amplifier using a monolithic semiconductor integrated circuit in order to reduce the number of bonding noccts and thus economize the area on a semiconductor chip.

(Structure of the Invention) In order to achieve the above object, the present invention provides a dual gout F
In two series of RF amplifiers using ET as an amplification element, by making each of the AGC voltage input gates of the FETs in each RF amplifier series common, the number of Dending Butts on the semiconductor chip for AGC voltage input can be reduced to one. This structure facilitates the integration of the FET circuit portion into a semiconductor integrated circuit, and economizes the area of the semiconductor chip.

(Explanation of Examples) The present invention will be explained in detail below using the drawings.

FIG. 3 shows a partially omitted essential circuit of an embodiment of the present invention. This is a case where the present invention is applied to the conventional circuit shown in FIG.
A circuit corresponding to the above, which is formed using a semiconductor integrated circuit.

Q4-Q5 are, for example, FETs for amplifying the VHF band, and their respective second gates G2
, G'2 are connected and led to one bonding terminal 41, which has UHF.

An AGC voltage as a VHF band amplifier circuit is applied via a resistor 42. 43 is a binorth capacitor.

In this circuit, the UHF and VHF band amplifier circuits are selected by the first gate Gi+G'1 of the signal input gate of each FET.
(by applying a cutoff voltage to

This is the normal selection switching method.
, D' by applying a cutoff voltage, if the AGC voltage input gate is shared as in the present invention,
Since +1 to +2V is normally applied as the AGC voltage, the FET voltage of the cut-off RF amplifier +Q,
This is because ■G2S is clamped to 7V.

As explained above, the present invention provides a dual group-1 FE
This is a radio frequency amplification circuit consisting of two series of RF amplifiers 9 having T as an amplifying element, in particular, the AGC voltage input gates of each FET of each series are connected in common, and the FET portion is integrated into a semiconductor integrated circuit.

(Effects of the Invention) As is clear from the above detailed explanation, the present invention provides a dual gate F as an amplifying element in which the main parts of two series high frequency amplifiers are monolithically integrated into a semiconductor circuit.
By integrally connecting each second gate of the ET, only one bonding terminal is required, and the AGC
It is designed to apply voltage, and has the advantage of reducing the number of terminals as a semiconductor chip, thereby reducing the chip area, and has great practical value when used in, for example, television tuners.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an outline of the configuration of a conventional example, FIG. 2 is a specific circuit diagram thereof, and FIG. 3 is a circuit diagram of a main part of an embodiment of the present invention. 1... UHF free frequency amplifier, 2... VHF radio frequency amplifier, 5... Next stage circuit, U... UHF reception input tuning circuit, ■... VHF reception input tuning circuit, H...・
Amplifier circuit part made into a semiconductor integrated circuit, H'... Amplifier circuit part made into a semiconductor integrated circuit, Ql, Q2, Q3
, Q4 +Qs...Dual gate field effect transistor. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 1 Figure 2 Figure 3 H' AGCλ

Claims (1)

[Claims] In a radio frequency amplifier in which two series of radio frequency amplification circuits having dual gate FETs as amplifying elements are provided corresponding to different radio frequency bands, each of the dual gate FETs in each series is connected to the input gate of the AGC voltage. A radio frequency amplifier characterized in that the AGC voltage can be applied from only one bonding pad on a semiconductor chip on which the semiconductor integrated circuit is formed by interconnecting them to form a semiconductor integrated circuit. .