Matters to Be Observed When Using This Product

■ When the capacitor is used in an AC circuit, especially in a high-frequency circuit, the capacitor generates heat because

of the alternating current flowing therethrough. If this self-heating by the capacitor is excessive, the capacitor may

deteriorate or generate smoke or even ignite. Confirm the self-temperature rise value of the capacitor under the actual

service condition and use the capacitor at the self-temperature rise value equal to or lower than the specified

self-temperature rise value.

Measure the self-temperature rise value at room temperature in a windless condition. Refer to the delivery specification

sheet to check detailed information on the self-temperature rise value.

The specified self-temperature rise value varies depending on capacitor types. For more detailed information about

this matter, please contact us.

■ Because the working temperature range of a capacitor varies depending on dielectric materials (film types), the working

temperature range in which the capacitor can be used is specified for each capacitor type.

Note, however, that working temperature ranges listed in a catalog are surface temperatures which are different from

ambient temperatures. When using the capacitor, make sure that (ambient temperature + self-temperature rise value

(within the specified value)), that is, the surface temperature of the capacitor is within the working temperature range.

■ If the capacitor is used in a temperature condition above the working temperature range, its loss tangent (tan δ) gets

larger, inducing self-heating, which leads to exceeding the allowable value. As a result, the dielectric film deteriorates

which can cause a short circuit failure that may lead to smoke generation or ignition. When a heat dissipation plate

of a different component or resistance generating high heat is present near the capacitor, radiant heat from such an

element is applied to a part of the capacitor, in which case the temperature of the capacitor can exceed the working

temperature range and smoke generation or ignition may occur. Make sure to check the surface temperature of

elements that serve as a heat source.

■ The chip-type laminated film capacitor is mounted directly on the board without a lead interposed between the capacitor

and the board. Because of this configuration, if the thermal expansion coefficient of the capacitor and that of the board

differ widely, due to temperature change, etc., after chip mounting, it creates mechanical stress which is applied to the

capacitor. This deforms the capacitor body or cracks its soldered part, thus impairing its performance. Examine and

check the capacitor sufficiently before mounting it on the board. In particular, when using a ceramic board, please

contact us before mounting the capacitor.

<Thermal expansion coefficients of boards and chip-type laminated film capacitors>

■ Radiant heat from a heat-carrying component present near the capacitor may raise the temperature of the capacitor

above the category temperature range. Be careful in such cases. The chip-type capacitor does not have the outer

casing that the lead-type capacitor has. If an exposed part of a live component is present near the capacitor, a short

circuit may be created through the capacitor. Exercise special caution when determining the location of the capacitor.

■ If the land area of the capacitor is large, a tombstone phenomenon (chip rising) is likely to occur when the volume of

solder is not proper. Give each type of capacitor recommended land dimensions as much as possible, even though it

is disadvantageous from the viewpoint of ensuring the mounter has sufficient mount clearance.

■ In the flow soldering process, a chip component is dipped in melted solder and resulting in a high temperature of the

component. The film capacitor has low resistance to heat. Avoid soldering it using the flow soldering process.

Applying heat directly to a capacitor from the lower surface of the printed board for repair work (using a hot plate, etc.)

may result in the degradation of the capacitor. This process must also be avoided.

23-Apr-25

Resin board

Paper

phenol

Paper

epoxy

Glass

epoxy

(PPS film)

ECHU(X)/(C)

Chip-type laminated film capacitor

1

～ 25

Thermal expansion

coefficient

(×10-6/°C)

1

～ 30

1

～ 15

Type

Item

　 Mounting conditions (chip-type) * Target capacitors: ECHU, ECWU, and ECPU

　 Circuit design (working temperature)

　 Board design

7

～ 8

Alumina

Ceramic board

70

(Plastic film)

ECPU(A)

10

(PEN film)

ECWU(X)/(C)

22