JP2020191389A - Resistor - Google Patents

Abstract

To provide a resistor that is less prone to a crack in a solder joint, an insulating substrate, etc.SOLUTION: Lead terminals 7a and 7b include a first crank portion CR1 bent in a direction away from a resistance substrate from a joint portion between the tip portion and internal electrodes 17a and 17b at a position where the lead terminals do not overlap with the internal electrodes 17a and 17b in a plan view. As a result, when the tip portions of the lead terminals 7a and 7b and the internal electrodes 17a and 17b are solder-bonded, a solder fillet (back fillet) is not formed in the first crank portion, such that the generation of thermal stress in the crank portion is alleviated and deterred.SELECTED DRAWING: Figure 4

Description

The present invention relates to a heat dissipation type power resistor (resistor for high power).

In the power control unit (PCU) of a vehicle such as a hybrid electric vehicle (HEV), a cement resistor has been conventionally used as a discharge resistor for high power to decharge a capacitor for voltage stabilization or a smoothing capacitor. Was there.

On the other hand, as a resistor that has a wider range of applications than cement resistors, it is designed to be mounted on a printed circuit board while attached to a heat sink, and is used in high-voltage, high-current environments (power resistors). Has been developed.

For example, in the power resistor described in Patent Document 1, a combination of a trace and a pad corresponding to an electrode is provided on the upper surface of a ceramic substrate, and the tip portion (tip compartment) of a metal terminal (lead) is provided on the combination. Are joined together and have a structure in which a protective coating is further formed on a resistance film formed on the union.

Japanese Patent Application Laid-Open No. 5-226106 (Patent No. 2904654)

The above-mentioned conventional resistor is a substantially rectangular shape made of a synthetic resin formed by joining a metal terminal (lead terminal) on an electrode to form an external connection terminal and forming a resistance element having a resistance film on a ceramic substrate. It has a body with a shape. FIG. 8 is an enlarged cross-sectional view of a joint portion between an electrode and a metal terminal in a conventional resistor. As shown in FIG. 8, of the tip portion of the metal terminal 107, the bent portion (crank) CR3 rising from the electrode 117 is located on the electrode 117 in the plane direction.

Therefore, when the tip portion of the metal terminal 107 is joined to the electrode 117 by the solder 125, a solder fillet F3 is formed between the bent portion and the electrode. Therefore, solder shrinkage / expansion due to thermal stress of the solder fillet F3 (indicated by reference numeral Z) ), And contraction / expansion (indicated by reference numeral Y) of the lead terminal due to thermal stress at the rising portion occurs.

Further, solder shrinkage / expansion (indicated by reference numeral X) due to thermal stress of the solder fillet F2 formed between the most advanced portion of the metal terminal 107 and the electrode occurs.

When a solder fillet is formed at the bent portion (crank) of the lead terminal in this way, cracks are generated in the solder due to the concentration of thermal stress, the solder cracks are extended, and the ceramic substrate 115 is also cracked. There is a risk.

Further, it is assumed that the cracks generated in the ceramic substrate 115 affect the resistor 113, resulting in a situation in which the function as a resistor is impaired, such as a change in the resistance value. Especially in the case of a resistor for in-vehicle use where there is a lot of vibration, since the operation of the resistor is directly linked to the safety of the vehicle, the occurrence of cracks in the solder joint and the substrate is an urgent issue.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a resistor for high power having a terminal structure that suppresses solder cracks and cracks in an insulating substrate.

The following configuration is provided as a means for achieving the above object and solving the above-mentioned problem. That is, the resistor of the present invention comprises a resistance substrate formed by forming a pair of internal electrodes with a resistor on an insulating substrate, and an insulating exterior material having a substantially rectangular shape as a whole covering at least the upper surface and side surfaces of the resistance substrate. A pair of external connecting conductors, one end of which is connected to each of the pair of internal electrodes, and the other end of which penetrates one side surface of the exterior material in the longitudinal direction and extends to the outside. A first crank portion that bends in a direction away from the resistance substrate at a portion covered with the exterior material, and a second crank portion that bends in a direction horizontal to the resistance substrate at a predetermined position extending from the first crank portion. The first crank portion is provided at a position separated from the joint portion between the one end portion of the external connecting conductor and the pair of internal electrodes by a predetermined distance. It is characterized in that it is arranged at a position where it does not overlap with the pair of internal electrodes in a plan view.

For example, the first crank portion is characterized in that it is bent so as to be separated from the resistance substrate in a substantially vertical direction. For example, in a direction horizontal to the resistance substrate, the length from the tip of the one end portion of the external connecting conductor to the first crank portion connects the one end portion of the external connecting conductor at the internal electrode. It is characterized by being longer than the length of the region that can be. Further, for example, a gap is formed between the outer lower surface of the first crank portion and the upper surface of the resistance substrate to avoid contact between the first crank portion and the resistance substrate. To do. For example, the one end portion and the internal electrode are separated from each other by a protrusion having a predetermined height provided on the lower surface side of the one end portion. For example, the protrusions having a predetermined height are arranged on both sides of the central portion of the pair of internal electrodes at substantially equal distances in the horizontal direction of the resistance substrate. Further, for example, the internal electrode and the one end portion of the external connecting conductor are connected by solder. Further, for example, the solder is filled in a gap formed so that the one end portion and the internal electrode are separated from each other. For example, the resistor is characterized in that it is formed so as to surround the outer periphery of each of the pair of internal electrodes. Further, for example, the resistor is formed so as to straddle the pair of internal electrodes.

According to the present invention, the crank portion, which is a portion where the external connecting conductor joined to the internal electrode of the resistor bends upward, is separated from the joint portion by a predetermined distance in the horizontal direction of the resistance substrate of the resistor. By arranging it at a position where it does not overlap with the internal electrodes when viewed in a plan view, even if stress due to thermal stress occurs in the crank portion, it is difficult for the stress to be directly applied to the electrodes, and the thermal stress is dispersed. As a result, it is possible to suppress the occurrence of solder cracks and cracks on the electrodes and the resistance substrate due to thermal stress.

It is external perspective view when the power resistor which concerns on embodiment of this invention is seen from the front side. It is an external perspective view when the power resistor which concerns on this embodiment is seen from the back side. It is a perspective view which shows a part of the internal structure of the power resistor which concerns on 1st Embodiment of this invention. It is a top view of the resistance substrate of the power resistor which concerns on 1st Embodiment. It is sectional drawing which cut | cut the resistor which concerns on 1st Embodiment along the arrow AA' line of FIG. It is a figure which shows the protrusion provided in the tip part of the lead terminal of the resistor which concerns on 1st Embodiment. It is a perspective view which shows a part of the internal structure of the power resistor which concerns on 2nd Embodiment of this invention. It is sectional drawing which cut | cut the resistor which concerns on 2nd Embodiment along the arrow BB'line of FIG. It is sectional drawing which shows the structural example of the resistance substrate of the conventional power resistor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1A is an external perspective view of the power resistor according to the first embodiment of the present invention when viewed from the front side, and FIG. 1B is an external perspective view of the power resistor when viewed from the back side. Further, FIG. 2 is a perspective view showing a part of the internal structure of the power resistor according to the first embodiment.

As shown in FIGS. 1A, 1B, and 2, in the power resistor 1 according to the first embodiment, a pair of internal electrodes 17a and 17b are formed on the surface of a rectangular-shaped insulating substrate 15 made of alumina or the like. Further, a resistance substrate 21 in which a resistor 13 is formed so as to connect the internal electrodes 17a and 17b is provided. The insulating substrate 15 maintains the heat dissipation performance in a power resistor corresponding to a large amount of power by reducing the thickness of alumina or the like to lower the thermal resistance.

In the resistance substrate 21, one end 8a, 8b of the pair of lead terminals 7a, 7b is connected to the internal electrodes 17a, 17b by soldering, ultrasonic bonding, or the like, and the other end side of the pair of lead terminals 7a, 7b is connected. , It has a structure exposed to the outside of the exterior body 3 (also referred to as a molded resin portion or an exterior resin portion) of the power resistor. The lead terminals 7a and 7b are made of, for example, copper, and the surface thereof is plated with tin or the like.

In the manufacturing process of the power resistor 1, either of the internal electrodes 17a and 17b and the resistor 13 may be formed first. Further, as the lead terminals 7a and 7b, a member having an insulating coating on the surface excluding the joints with the internal electrodes 17a and 17b can be used.

Further, the lead terminals 7a and 7b as the external connecting conductor are not limited to the form shown in FIG. 1A and the like, and for example, another electric device such as a screw is attached to the tip of a portion of the exterior body 3 exposed to the outside. A harness electric wire in which a round terminal (ring terminal) that can be connected to a component or the like is crimped by caulking or the like may be used. Further, a lead wire having a flat tip may be used.

As shown in FIG. 2, the resistance substrate 21 is covered with an insulating resin (mold resin) such as epoxy resin on the upper surface (front surface) and side surfaces on which the resistor 13 and the like are formed, and the lower surface side is the main body portion of the resistor 1. It is exposed to the outside of the exterior body 3. A through hole 5 is formed in the exterior body 3 near the end opposite to the side on which the resistance substrate 21 is located, and the through hole 5 is used as a screw hole or a fastening hole, and the power resistor 1 is used as a housing for an external device. By attaching it to a body (aluminum die-cast) or the like, the structure is such that the heat generated by the resistor 13 can be conducted to the housing of the mounting destination and dissipated.

In the present embodiment, the exterior body 3 will be described as an insulating resin, but the present invention is not limited to this, and a structure in which a resistance substrate is sealed with an insulating material in an insulating case such as ceramic may be used.

A cylindrical bush made of a predetermined metal (for example, stainless steel, copper, iron, etc.) may be fitted inside the through hole 5 in order to prevent slippage during reinforcement or screw fastening. The outer size of the exterior body 3 is, for example, the same size as the general-purpose package (TO-247).

The internal electrodes 17a and 17b are made of, for example, a silver-based or silver-palladium-based metal material, and in the case of a silver-palladium-based material, it is desirable that the internal electrodes are palladium-rich. Further, the resistor 13 is a thick film resistor made of, for example, a ruthenium oxide-based material, and is formed by screen printing or the like.

In the resistance substrate 21, the entire upper surface of the insulating substrate 15 other than the joint between the internal electrodes 17a and 17b and the lead terminals 7a and 7b which are external connecting conductors is covered with the glass protective film (glass coat) 31. A resin protective film may be formed on the glass protective film 31. The dimensions of the internal electrodes 17a and 17b may be larger than the portion not covered by the glass protective film (the portion left open for solder connection).

FIG. 3 is a plan view of the resistance substrate 21 of the power resistor 1. Further, FIG. 4 is a cross-sectional view of the resistance substrate 21 cut along the line AA ′ of FIG.

As shown in FIGS. 2 and 4, the lead terminals 7a and 7b have a predetermined portion of the tip portion (one end portion 8a and 8b) bonded to the internal electrodes 17a and 17b, and the resistance substrate is bonded from the bonded portion. It has a first crank portion CR1 that bends upward (in a direction away from the surfaces of the insulating substrate 15 and the resistance substrate 21) at a position that is horizontally separated from the 21 and does not overlap the internal electrodes 17a and 17b in the vertical direction. ..

Further, the lead terminals 7a and 7b are bent in the horizontal direction (direction along the surfaces of the insulating substrate 15 and the resistance substrate 21) at a position extending upward by a predetermined length from the first crank portion CR1. Has.

The lead terminals 7a and 7b have a crank shape as described above to prevent contact with the glass protective film (glass coat) 31 covering the surface of the resistor 13 and the surface of the resistance substrate 21 and to pull from the outside. It can absorb stress and maintain its mechanical strength as an external connecting conductor.

As shown in FIG. 3, the internal electrodes 17a and 17b are located inside the insulating substrate 15 at a predetermined distance K from the end. By doing so, even if the resistor 13 having a pattern surrounding the outer circumferences of the internal electrodes 17a and 17b is formed, the heat generated by the resistor 13 can be dispersed. The pattern of the resistor can be appropriately selected according to the required resistance value and the like.

As shown in FIGS. 3 and 4, the length L1 from the tip end portion of the lead terminals 7a and 7b joined to the internal electrodes 17a and 17b to the first crank portion CR1 is preferably the internal electrode 17a, The length of the solder-connectable region of 17b is longer than L2 (L1> L2). Regarding L1 and L2, for example, there is a relationship of L2: (L1-L2) = 2: 1.

Since the lead terminals 7a and 7b and the internal electrodes 17a and 17b are in the above positional relationship, when the tip portions of the lead terminals 7a and 7b are solder-connected to the internal electrodes 17a and 17b, the first crank portion CR1 is inside. It is formed at a position away from the electrodes 17a and 17b and does not overlap with the internal electrodes 17a and 17b when viewed from directly above.

Here, in the conventional resistor shown in FIG. 8, the cause of cracks in the solder 125 is that the bent portion CR3 of the metal terminal 107 and the internal electrode 117 are at the same position in a plan view, so that the metal terminal 107 is heated. This is because the stress (reference numerals Z, Y) applied when expanding and contracting due to the above is concentrated on the solder fillet F3 formed on the outside of the bent portion CR3.

Therefore, in the power resistor according to the first embodiment, the lead terminals 7a and 7b rise up by arranging the first crank portion CR1 of the lead terminals 7a and 7b at a predetermined distance from the internal electrode 17a. The thermal stress Y generated in the portion (between the first crank portion CR1 and the second crank portion CR2) is less likely to be directly applied to the internal electrodes 17a and 17b. This structure can be expected to have the same effect even when the lead terminals 7a and 7b are connected to the internal electrodes 17a by a method other than soldering (for example, ultrasonic bonding, welding, etc.).

Further, when the lead terminals 7a and 7b are connected to the internal electrodes 17a by soldering, the solder fillet is not formed on the outside of the first crank portion CR1, so that the conventionally generated solder fillet is pulled at the bent portion (FIG. FIG. Reference numeral Z) of 8 does not occur.

As a result, the power resistor according to the first embodiment is different from the configuration in which the crank portion is located on the internal electrode as in the resistance substrate of the conventional power resistor shown in FIG. 8, and the first crank portion CR1 , The stress due to thermal expansion or contraction of the lead terminal is dispersed. As a result, the occurrence of cracks in the first crank portion CR1 can be suppressed.

The above-mentioned technical effect can be expected by separating the first crank portion CR1 formed on the lead terminals 7a and 7b from the internal electrodes 17a and 17b by a predetermined distance, but more preferably, it is substantially perpendicular to the resistance substrate 21. The thermal stress can be more effectively dispersed when the first crank portion CR1 is bent so as to be separated in a direction, that is, when the first crank portion CR1 is substantially perpendicular to the resistance substrate 21.

For example, when the first crank portion bent by about 45 ° in the direction away from the resistance substrate 21 is formed, the thermal stress Y generated at the rising portion of the lead terminals 7a and 7b is applied in the oblique direction, and the lead terminals 7a, Stress may affect the joint between the 7b and the internal electrodes 17a and 17b. Therefore, it is desirable that the first crank portion CR1 is bent so as to be separated from the resistance substrate 21 in a substantially vertical direction.

When the first crank portion CR1 of the lead terminals 7a and 7b is arranged at a predetermined distance from the internal electrodes 17a and 17b and in a region corresponding to the upper part of the insulating substrate, the entire resistor expands and contracts due to heat. Sometimes it's well-balanced.

The length L1 from the tip of the lead terminals 7a and 7b to the first crank portion CR1 is shorter than the length L2 of the solder-connectable region of the internal electrodes 17a and 17b (L1 <L2), or When the length L1 from the tip of the lead terminals 7a and 7b to the first crank portion CR1 is substantially equal to the length L2 of the solder-connectable region of the internal electrodes 17a and 17b (L1 = L2), the lead By shifting the tips of the terminals 7a and 7b from the center of the internal electrodes 17a and 17b to the predetermined positions and arranging the first crank portion CR1 so as to protrude from the internal electrodes 17a and 17b, the first crank portion CR1 In, the stress due to the thermal expansion or contraction of the lead terminal can be dispersed.

Further, the power resistor according to the first embodiment is the tip portions 8a and 8b of the lead terminals 7a and 7b as shown in FIG. 4, and is located on the lower surface side of the portion solder-connected to the internal electrodes 17a and 17b. A plurality of protrusions P1 to P4 having a predetermined height are formed. The protrusions P1 to P4 are arranged at the tip portions of the lead terminals 7a and 7b, for example, as shown in FIG.

Here, as shown in FIGS. 4 and 5, the protrusions P1 to P4 are the distances from the horizontal center C of the internal electrodes 17a and 17b to the protrusions P1 and P3, and the protrusions P2 and P4 from the center C. Are arranged so that the distances to are equal.

By providing the protrusions P1 to P4 in this way, a gap having a gap dimension H is formed between the tip portions of the lead terminals 7a and 7b and the internal electrodes 17a and 17b as shown in FIG. As a result, it is possible to suppress the formation of a metal compound due to the direct contact between the lead terminal and the internal electrode, and to keep the thickness of the solder filled between the lead terminal and the internal electrode constant.

In addition, due to the protrusions P1 to P4, even if the lead terminal is pressed against the internal electrode side when the tip portions of the lead terminals 7a and 7b are soldered to the internal electrodes 17a and 17b, the distance between the tip portion and the internal electrode is reached. Can be maintained in a state parallel to each other, and the soldering work can proceed smoothly.

As described above, in the resistor according to the first embodiment, one end of the pair of external connecting conductors is connected to each of the pair of internal electrodes, and the other end is one side surface of the exterior material of the resistor in the longitudinal direction. A first crank portion that rises and bends in a direction away from the surface of the resistance substrate is formed on one end side of the portion of the portion covered with the exterior material of the pair of external connecting conductors that extends through the resistor substrate. At the same time, a second crank portion that bends in the horizontal direction is formed on the surface of the resistance substrate at a predetermined position extending from the first crank portion, and the first crank portion is paired with one end of the external connecting conductor. It has a configuration in which it is arranged at a predetermined distance from the joint with the internal electrode.

That is, the thermal stress is applied by separating the first crank portion to which the most stress is applied in the external connecting conductor from the internal electrode and arranging the first crank portion at a position where the first crank portion does not overlap the upper surface portion of the internal electrode when viewed in a plan view. Can be dispersed. In particular, when the external connecting conductor and the internal electrode are solder-bonded, a solder fillet (back fillet) is not formed on the first crank portion.

As a result, the generation of thermal stress in the first crank portion is relaxed and suppressed, thermal contraction and thermal expansion of the lead terminal can be avoided, and cracks in the solder portion, electrodes, insulating substrate and the like can be avoided.

Further, even when the resistor is used as a resistor for constant discharge exposed to a high temperature of 150 ° C. or higher, or installed in an in-vehicle environment where there is a lot of mechanical vibration, obstacles such as disconnection and short circuit of the conduction path are observed. Can be suppressed.

<Second embodiment>
FIG. 6 is a perspective view showing a part of the internal structure of the power resistor 10 according to the second embodiment of the present invention. Further, FIG. 7 is a cross-sectional view of the resistance substrate 51 cut along the arrow line BB'of FIG.

The power resistor according to the second embodiment has the same outer size as the general-purpose package (TO-247), for example, as the power resistor according to the first embodiment. .. Here, the description of the same configuration as that of the first embodiment will be omitted.

As shown in FIGS. 6 and 7, the lead terminals 47a and 47b of the power resistor 10 according to the second embodiment have the tip portions (one end portion) 48a and 48b having the power according to the first embodiment. The lead terminals 7a and 7b in the resistor are formed longer than the tips 8a and 8b (reference numeral L1 in FIG. 3).

The tip portions (one end portion) 48a and 48b of the lead terminals 47a and 47b are joined to the internal electrodes 57a and 57b by solder 65, respectively. Note that F4 is a solder fillet formed at the tips of the lead terminals 47a and 47b.

The lead terminals 47a and 47b are substantially vertical in the horizontal direction of the resistance substrate 51 from the joint portion with the internal electrodes 57a and 57b and at positions separated from the internal electrodes 57a and 57b and the insulating substrate 55 (these external regions). It has a first crank portion CR4 that bends in a direction (a direction away from the surface of the insulating substrate 55).

Further, the lead terminals 47a and 47b have a second crank portion CR5 that bends in the horizontal direction (direction along the surface of the insulating substrate 55) at a position extending in the vertical direction by a predetermined length from the first crank portion CR4.

In the power resistor 10, a resistor 53 is formed on the entire surface of the insulating substrate 55 between the internal electrodes 57a and 57b in order to improve the pulse resistance and the like. Therefore, the internal electrodes 57a and 57b are arranged at positions along both ends of the insulating substrate 55. The surface of the resistor 53 is provided with a glass protective film (glass coat) or a resin protective film (not shown).

As described above, in the power resistor according to the second embodiment, the crank portion formed in the lead terminal is arranged outside the region of the resistance substrate 51 when viewed in a plan view, so that the crank portion inevitably becomes the resistance substrate 51. It is formed at a position away from the upper surface of the.

As a result, as shown in FIG. 7, a sufficient distance L3 between the end portion of the first crank CR4 and the internal electrode can be secured, and the generation of thermal stress in the crank portion is alleviated and suppressed, so that the heat of the lead terminal is suppressed. It is possible to suppress the occurrence of cracks in the solder portion, electrodes, insulating substrate, etc. due to shrinkage / thermal expansion.

In the present embodiment, the bending of the first crank portion CR4 is not limited to the vertical direction, but the bending in the vertical direction enables miniaturization and space saving.

Further, in the present embodiment, the length from the tip of one end 48a, 48b of the lead terminals 47a, 47b to the first crank portion CR4 is secured longer than the lead terminal connectable region of the internal electrodes 57a, 57b. As a result, the first crank portion CR4 is arranged in the internal electrode and the outer region of the insulating substrate. This is to improve heat dissipation by securing a large area of the lead terminal, but the present invention is not limited to this. For example, regardless of the length, the tips of the lead terminals 47a and 47b are shifted from the center of the internal electrodes 57a and 57b toward the end at a predetermined position, and the first crank portion CR4 is moved to the internal electrodes 57a and 57b (insulating substrate 55). ) May be arranged so as to protrude from.

1,10 Power resistor 3,43 Exterior body 5,45 Through hole 7a, 7b, 47a, 47b Lead terminal (external connection conductor)
8a, 8b, 48a, 48b One end of lead terminal 13 Resistor 15,55 Insulation substrate 17a, 17b, 57a, 57b Internal electrode 21,51 Resistance substrate 25,65 Solder 31 Glass protective film (glass coat)
CR1 to CR5 Cranks P1 to P4 Protrusions

Claims (10)

A resistor substrate in which a resistor and a pair of internal electrodes are formed on the insulating substrate,
An insulating exterior material that covers at least the upper surface and side surfaces of the resistance substrate and has a substantially rectangular parallelepiped overall shape.
A pair of external connecting conductors, one end of which is connected to each of the pair of internal electrodes, the other end penetrating one side surface of the exterior material in the longitudinal direction and extending outward, and the exterior. At the portion covered with the material, a first crank portion that bends in a direction away from the resistance substrate and a second crank portion that bends in a direction horizontal to the resistance substrate at a predetermined position extending from the first crank portion With the pair of external connecting conductors formed
The first crank portion is located at a position separated from the joint portion between the one end portion of the external connecting conductor and the pair of internal electrodes by a predetermined distance, and does not overlap with the pair of internal electrodes in a plan view. A resistor characterized by being placed in. The resistor according to claim 1, wherein the first crank portion is bent so as to be separated from the resistance substrate in a substantially vertical direction. The length from the tip of the one end of the external connecting conductor to the first crank in the horizontal direction with the resistance substrate is such that the one end of the external connecting conductor is connected at the internal electrode. The resistor according to claim 1 or 2, wherein the resistor is longer than the length of the possible region. Claim 1 is characterized in that a gap is formed between the outer lower surface of the first crank portion and the upper surface of the resistance substrate so as to avoid contact between the first crank portion and the resistance substrate. The resistor according to any one of 3 to 3. The resistor according to any one of claims 1 to 3, wherein the one end portion and the internal electrode are separated from each other by a protrusion having a predetermined height provided on the lower surface side of the one end portion. .. The resistor according to claim 5, wherein the protrusions having a predetermined height are arranged at substantially equal distances in the horizontal direction of the resistance substrate on both sides of the central portion of the pair of internal electrodes. The resistor according to any one of claims 1 to 6, wherein the internal electrode and the one end portion of the external connecting conductor are connected by solder. The resistor according to claim 7, wherein the solder is filled in a gap formed by separating the one end portion and the internal electrode. The resistor according to claim 1, wherein the resistor is formed so as to surround the outer periphery of each of the pair of internal electrodes. The resistor according to claim 1, wherein the resistor is formed so as to straddle the pair of internal electrodes.