JP2934667B2 - Multilayer hybrid integrated transmission filter - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission filter using a multilayer hybrid integrated circuit using a multilayer body including a network of a composite capacitor, a composite inductor, and a composite resistor in an integrated multilayer structure.

(Prior Art) Conventional transmission filters include those using a passive filter and those using an active filter as shown in FIG. In FIG. 5, a is an active filter section, and b is an equalizer section for making the group delay amount characteristic constant, each of which is composed of a resistor R, a capacitor C, and an operational amplifier A.

(Problems to be Solved by the Invention) However, as shown in FIG.
In the figure, the horizontal axis represents the frequency f, and the left vertical axis represents the attenuation (AT
T), the right vertical axis indicates the amount of group delay (GD)) when it is intended to realize a band-pass filter, which cannot be realized only by a passive filter. This is because an inductor having a Q of 250 or more is required to obtain a steep attenuation characteristic, and such an inductor is difficult to obtain. That is, Q representing the small loss of the inductor is Q = ωL / R (ω: angular frequency, L: inductance,
R: loss), the inductor cannot obtain a Q of 250 or more because of the resistance of the winding and the high-frequency loss of the core, and since the Q is low, a steep attenuation characteristic as theoretical cannot be obtained.

On the other hand, the active filter as shown in FIG. 5 is composed of the capacitor C, the resistor R and the operational amplifier A as described above, and the Q (= 1 / ωCR) of the capacitor C can easily be several hundred or more. Although a steep attenuation characteristic can be easily obtained, when a large number (16 in the illustrated example) of operational amplifiers A are required as shown in FIG. 5, the power consumption becomes large. is there. Further, since a large number of capacitors C and resistors R are required, there is a problem that an occupied space becomes large.

The present invention has been made in view of the above-described problems of the related art, and has as its object to provide a transmission filter having a structure in which steep attenuation characteristics can be obtained, miniaturization and reduction in power consumption are achieved.

(Means for Solving the Problems) In order to achieve the above object, the present invention forms and sinters each network and wiring pattern including a composite capacitor, a composite inductor, and a composite resistor, respectively, in an integrated laminate structure, and A passive filter that functions as an equalizer by a network of the inductor and a part of the network of the capacitor, including a stacked body having terminals formed on side surfaces thereof, and an operational amplifier including an integrated circuit mounted on the stacked body; In addition, an active filter functioning as a filter body is constituted by the other part of the capacitor network, the resistor network and the operational amplifier, and the active filter and the passive filter are connected and used.

(Operation) The transmission filter of the present invention has the above configuration, and exhibits an equalizer function in which a steep attenuation characteristic can be obtained with an active filter and a low Q value can be obtained with a passive filter.

(Embodiment) FIG. 1 is a sectional view showing a transmission filter according to the present invention, and FIG. 2 is a perspective view thereof. 1 and 2, reference numeral 1 denotes a laminated body in which a capacitor network 2 including a composite capacitor therein, an inductor network 3 including a composite inductor, and a resistor network 9 including a composite resistor are stacked and integrated. . As shown in FIG. 1, the capacitor network 2 has a plurality of capacitors formed therein by alternately laminating dielectrics 4 and electrodes 5 made of a metal film by a printing method or another film forming technique. The electrode of each capacitor is connected to a predetermined one of the plurality of terminals 6 formed on the side surface of the multilayer body. The inductor network 3 is also formed by laminating a ferrite 7 and a conductor film 8 by a printing method or the like, and forming the conductor film 8 in a coil shape or a spiral shape.

The resistor network 9 includes a glass layer 10 formed on the inductor network 3 and a conductor layer formed thereon.
11 and a plurality of resistance layers 12, and a glass layer 13 covering these surfaces. Reference numeral 14 denotes a pad formed on the surface of the laminate 1 and constitutes a part of a wiring pattern.
The laminate 1 is integrally sintered at, for example, about 800 ° C.

Reference numeral 15 denotes an IC chip in which terminals 16 are connected to and fixed to pads 14 on the surface of the laminate 1 by solder 17, and constitutes an operational amplifier. The IC chip 15 may be mounted on both sides of the laminate 1.

FIG. 3 shows a circuit formed by the laminated body 1 and the IC chip 15 shown in FIGS. 1 and 2, wherein 18 is an active filter and 19 is a passive filter. The active filter 18 connects the operational amplifier 20 in the IC chip 15, the resistor 21 included in the resistor network 9, and a part of the capacitor 22 in the capacitor network 2 via the wiring pattern including the pad 14 and the terminal 6. And a filter main body for obtaining steep attenuation characteristics. The passive filter 19 is constituted by the remaining capacitor 22 of the capacitor network 2 in the multilayer body 1 and the inductor 23 in the inductor network 3.
It functions as an equalizer for stabilizing the group attenuation shown in the figure. As shown in FIG. 3, the active filter 18 and the passive filter 19 are connected and used.

Since the passive filter 19 functioning as an equalizer portion includes the inductor 23, a high Q value cannot be obtained, but the function for stabilizing the group delay amount can be sufficiently exhibited. Since the active filter 18 includes the capacitor 22 and does not include the inductor 23, a high Q value is obtained, and the filter inherently functions, and a steep attenuation characteristic is obtained.

Note that the present invention can be applied not only to a band-pass filter but also to other filters.

(Effects of the Invention) According to the present invention, the main body of the filter is constituted by an active filter, and the equalizer is constituted by a passive filter which does not require power and is used by being connected to the active filter. As a result, steep attenuation characteristics can be obtained, and power consumption can be reduced due to the reduction in the number of operational amplifiers.

Further, since the capacitor, the inductor, the resistor, and the like are formed by the integrally laminated structure, the whole is compacted, the occupied space is largely reduced, and the miniaturization is achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a transmission filter according to the present invention, FIG. 2 is a perspective view thereof, FIG. 3 is an example of the circuit thereof, and FIG. FIG. 5 is a circuit diagram of a conventional transmission filter using only an active filter. 1: laminate, 2: capacitor network, 3: inductor network, 4: dielectric, 5: electrode, 6: terminal, 7: ferrite, 8: conductor film, 9: resistance network, 10: glass layer, 11:
Conductor layer, 12: resistive layer, 14: pad, 15: IC chip, 18: active filter, 19: passive filter, 20: operational amplifier, 21: resistor included in resistor network, 22: capacitor included in capacitor network, 23: Inductor included in inductor network

Continuation of the front page (56) References JP-A-62-196811 (JP, A) JP-A-57-68913 (JP, A) JP-A-59-4406 (JP, U) JP-A-63-3190 (JP) , U) Japanese Utility Model Showa 57-39124 (JP, U)

Claims (1)

(57) [Claims] 1. A laminated body in which respective networks and wiring patterns each including a composite capacitor, a composite inductor, and a composite resistor are formed into an integrally laminated structure, sintered, and terminals are formed on side surfaces, and mounted on the laminated body. And a passive filter functioning as an equalizer by the network of the inductor and a part of the network of the capacitor, and the other part of the capacitor network, the resistor network, the operational amplifier, and the like. , An active filter functioning as a filter main body is configured, and the active filter and the passive filter are connected to be used.