JPS643238Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the front end section of an FM radio receiver, and relates to its modularization.

Conventionally, the front end section had circuit elements formed on the surface of a ceramic substrate, but ceramic substrates are expensive, and the front end module made of conventional hybrid integrated circuits was not suitable for inexpensive FM radio receivers. . Furthermore, in recent years, FM radio receivers have become less expensive, smaller, and thinner, and the conventional method of separately forming semiconductor integrated circuits and other components has reached its limits. As is well known, the front end section includes an input circuit, a high frequency amplification circuit, a mixing circuit, and a local oscillation circuit, and includes a large number of high frequency transformation coils, tuning coils, oscillation coils, and capacitors. It is made up of a package in which high-frequency amplification transistors and local oscillation transistors for the front end are molded, a hybrid IC in which chip capacitors and resistors are arranged, and a printed circuit board into which these packages and high-frequency transformation ICs are incorporated. Furthermore, since they require a shield case, they tend to become larger. Incidentally, the other amplification stages except the front end section are integrated into a single chip, so there is relatively little problem in miniaturization.
As mentioned above, there was room for improvement in the front end section.

As mentioned above, the front end section is formed by incorporating multiple parts, which increases the size of the front end, and the circuit constants vary widely depending on the arrangement and mounting condition of those parts, leading to defects. The disadvantage was that the rate was high, and there was instability that required modification of some circuit constants.

The present invention has been developed in view of the above, and its main purpose is to improve the reliability of the front end section by integrally forming front end circuit elements or components on the lead frame. .

Another purpose of the front end module of the present invention is to make the front end portion smaller and thinner. Still another object is to provide an inexpensive front end module by forming the front end portion on a lead frame.

Another object of the present invention is to provide a front end module that is easy to manufacture and has excellent mass productivity by using a lead frame.

Another objective is to provide a front end that can be easily integrated into an FM radio receiver.

The present invention was made to achieve the above-mentioned purpose, and it distinguishes between circuit elements in the front end section that do not require adjustment and those that require adjustment, and leads the former. The front end module is formed in the lead frame by assembling it into a frame and sealing it with resin, and then incorporating the latter into the lead frame after resin sealing.

Hereinafter, the front end module of the present invention will be explained based on the drawings.

FIG. 1 is a perspective view showing the appearance of a resin-sealed module in which front-end circuit elements and parts are incorporated. Reference numeral 1 denotes a resin sealing body 1 made of resin, in which openings 2 ₁ to 2 ₃ are formed. Coils L ₁ to L ₃ are assembled into the openings 2 ₁ to 2 ₃ after resin sealing. The coils L ₁ and L ₂ are high frequency coils for adjusting inductance, and are fixed coils or spring coils having predetermined characteristics. As shown in FIG. 2, the coil _L3 is a high frequency coil having a core 5 for adjusting inductance, and has a planar electrode 4 on its bottom surface.
Reference numeral 3 denotes a lead, and the external lead-out portion thereof may have a shape having a bent portion or a shape protruding in the horizontal direction. Further, reference numeral 11 indicates that the external lead-out portion of the lead is cut off. Incidentally, the coil _L3 will be hereinafter referred to as a variable coil.

FIG. 3 is a circuit diagram showing one embodiment of the front end section. In FIG. 3, 6 is an input terminal, 7 is an output terminal, 8 is a power terminal, and 9 is a ground terminal. Reference numeral 10 denotes an element (chip) in which a high frequency amplification transistor, a transistor for a mixing circuit section, a transistor for a local oscillation circuit, a bias resistor, etc. are integrated into semiconductors. _C1 to _C3 are capacitors,
R ₁ to R ₃ are resistors, coil L ₁ is a tuning coil, coil L ₂ is a local oscillation coil, and L ₃ is an intermediate frequency transformer consisting of a variable coil. Capacitor C ₁
~ _C3 is formed by a chip capacitor. Also,
Resistors R ₁ to R ₃ and capacitors of relatively small capacitance C ₅
~ _C8 may be formed on a semiconductor substrate. VC ₁ and VC ₂ are variable capacitors. If the front end uses a variable capacitance diode, it will be easier to miniaturize the front end module, and all circuit elements and components of the front end can be formed on one lead frame, resulting in improved electrical characteristics. Stable and reliable.

As is clear from Figure 3, the front end section contains many circuit parts that require adjustment.
The front end module of the present invention is one in which these circuit parts or elements are formed on a lead frame.

FIG. 4 is a plan view showing a state in which the circuit components and elements shown in FIG. 3 are assembled into a lead frame. Components corresponding to circuit components and elements in FIG. 3 are given the same reference numerals. In the front end section of Fig. 3, variable capacitors VC ₁ and VC ₂
All other circuit components and elements except for are formed within the area indicated by the dashed line. The lead frame includes a tab 12 to which the semiconductor integrated circuit element 10 is connected, a tab lead 13 that supports the tab 12, a lead having a tongue to which the circuit element is connected, and a portion connected to the semiconductor integrated circuit element 10 by a wire 14. It is formed by a lead having a diameter and an outer frame, etc. that supports the lead (not shown).

Now, each lead 3 will be explained. The lead 3A has its external lead-out portion cut off, and the tongue piece 3B of the lead 3A is connected to one electrode of the variable coil _L3 , the other tongue piece 3C is connected to one electrode of the chip capacitor _C6 , and the tab 12 The lead portion 3D extending in the direction is connected to the chip 10 by a wire 14. And lead 3A is line 1 in Figure 3.
It corresponds to 5. The lead 3E is connected to the chip 10 by a wire 14, a tongue piece 3F connected to one electrode of the coil _L3 , a tongue piece 3G connected to the electrode of the capacitor _C6 , a tongue piece 3H connected to the electrode of the coil _L1 . It is formed from a lead portion 3I. Further, chip capacitors C ₁ to C ₃ are installed so as to be installed between the leads 3J. Further, the lead 3E corresponds to the line 16 in FIG. Lead 3 like this
Since A and 3E are used only for connecting the internal circuit of the front end section, the external lead-out portions of the leads are cut off to prevent noise signals from being mixed in. Further, the lead portion may be connected without providing a tongue piece like the chip capacitors C ₁ to C ₃ .
Further, the tip of the lead 3J extends to and contacts the tab lead 13. And one end of lead 3 ₀ 3P
is connected to one electrode of coil L ₁ , and the other lead 3 ₀
A part of the lead extends in the direction of the tab 12, and its tip is connected to the semiconductor integrated circuit element 10 by a wire 14, and the other lead part is connected to one electrode of the chip capacitor _C5 . Other chip-like elements are similarly incorporated into the lead frame by soldering or the like. As mentioned above, the lead frame can have various shapes depending on the circuit connection. Therefore, it is clear that the shapes of the lead portions are different in circuits other than the front end shown in FIG.

In this manner, the electrodes of a chip-like element such as a chip capacitor that does not require adjustment are connected to the tongues of the leads by solder. On the other hand, the coils L ₁ , L ₂ and variable coil L ₃ that require adjustment are formed in the openings 2 _{1 to 2} formed in the resin sealing body 1 after the chip-like element is assembled into the lead frame and sealed with resin. 2 ₃
is inserted into the Openings 2 ₁ to 2 ₂ are formed after resin sealing. Tongue pieces 3B, ₃ extending from the leads 3A, 3E, 3K, 3M from the wall surface of the opening 23
F, 3I, 3N protrude, and the tongue pieces 3B,
The electrodes of the variable coil _L3 are connected to 3F, 3I, and 3N by soldering or the like. Further, the electrodes of the coils L ₁ and L ₂ are similarly connected to the tongue pieces protruding from the wall surface of the opening 2 ₂ . Furthermore, the external lead-out portion 3 of the lead
Q, 3R are variable capacitors VC ₁ ,
Connected to VC ₂ . And input terminal 6 is terminal 3
S, the output terminal is terminal 3M, and the power supply terminal 8 is terminal 3T. The external lead-out portions of the other leads are connected to the ground terminal 9 by external wiring or the like.

FIG. 5 is a sectional view showing the attachment of the variable coil _L3 . The electrode of the variable coil _L3 may be a flat electrode that can be easily connected to the protruding tongue piece 30 of the lead. C indicates a chip capacitor, 31
is solder.

FIG. 6 is a perspective view showing an embodiment in which the variable coil L is installed in a different position. An opening 20 is formed from the side surface of the resin-sealed module 1, and a tongue 30 protrudes from the wall surface 21 of the opening 20. The electrode 4 of the variable coil L is bonded to the tongue 30 by solder or the like. Reference numeral 22 indicates an ear portion for attachment.

Incidentally, the coils L ₁ and L ₂ may be molded onto the resin sealing body 1 without being attached after forming an opening in the resin sealing body 1 as long as predetermined characteristics are obtained.

While conventional transfer mold type semiconductor integrated circuits simply mounted a semiconductor chip on the tab of a lead frame, the present invention combines chip-shaped circuit elements, variable coils, etc. onto the lead frame. Integrated circuits can be formed, and the front end can be formed on a lead frame. That is, since the lead frame of the present invention has tongues and the like on the leads, various circuit elements can be formed, and various circuit elements can be incorporated into the lead frame. In this way, it becomes possible to incorporate the circuit of the front end section into the lead frame, facilitating mass production, and thereby reducing the manufacturing cost of the front end module.

Of course, the chip-shaped circuit element may be connected to the lead portion by solder or conductive paste. Also,
It is recommended that the thickness of the lead frame be slightly thicker than normal ones. Furthermore, the pitch of the external lead-out portion of the lead is relatively wide.

In addition, if the chip-shaped circuit element and its lead part are covered and fixed with a coating material such as resin or molten glass after the chip-shaped circuit element is bonded to the lead part, the circuit during resin sealing will be better. Since elements can be prevented from falling off, peeling, etc., the defect rate during mass production can be reduced.

As described above, the front-end module of the present invention makes it possible to form circuits on a lead frame, which makes it possible to make the front-end module smaller and thinner, thereby making it possible to construct a compact FM radio receiver.
Furthermore, since the front-end circuit can be formed on the lead frame, mass production is easy, the manufacturing cost can be reduced, and the number of steps required for installation into an FM radio receiver can be reduced, making this an extremely effective solution.

Furthermore, since the front end section can be formed from approximately one resin-sealed module, it is easier to adjust the front end section, reducing the defective rate and creating a highly reliable front end section. We can provide modules.

Of course, each chip-shaped element is covered with resin, which not only reduces the mutual interference of high-frequency signals between the elements, but also reduces the stray capacity of the element over time due to dust etc. adhering to the substrate as in the conventional case. Since this method does not cause any physical change, it is also effective as a vehicle-mounted receiver, and can provide a highly reliable front-end module for a radio receiver.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of a front end module according to the present invention. FIG. 2 is a perspective view of the variable coil. FIG. 3 is a circuit diagram of the front end section. FIG. 4 is a plan view of the lead frame of the front end module according to the present invention. FIG. 5 is a sectional view showing how the variable coil is attached. FIG. 6 is a perspective view showing different mounting states of the variable coil. 1: Resin sealing body, 2 ₁ to 2 ₃ : opening, 3: lead, L ₁ , L ₂ : coil, L ₃ : variable coil, C ₁ to
_C8 : Chip capacitor.

Claims (1)

[Scope of utility model registration request] A semiconductor integrated circuit in which each electrode of a chip-shaped capacitor and resistor among the tuning coil, capacitor, and resistor of the front end part of a radio receiver is fixed to the internal lead of a lead frame, and also includes a high-frequency amplification circuit. The back side of the element is fixed to the internal leads, and the parts arranged and fixed to these internal leads are sealed in a resin molded body, and the tongue piece of the internal lead exposed from the opening of the resin molded body is adjusted. A front-end module characterized in that it is a hybrid integrated circuit formed by fixing planar electrodes of a tuning coil that requires.