Datasheet

2 of 9
Apr. 1, 2008
CLASSIFICATION
SPECIFICATIONS
No.
SUBJECT
PAGE
DATE
151S-ECJ-SS018E
Multilayer Ceramic Chip Capacitor
Common S
p
ecification
(
Precautions for Use
)
Note ;
2-1-7. Capacitance aging
The ceramic dielectrics of the Capacitors (Class 2) have capacitance aging. Accordingly, when the Capacitors
are used for the circuits, which require a narrow capacitance allowable range, such as time constant circuits,
pay due consideration to capacitance aging for use.
2-1-8. Piezoelectricity
Dielectrics used for the Capacitors (Class 2) may cause the following Piezoelectricity (or Electrostriction).
(1) If the signal of a specific frequency is applied to the Capacitors, electric and acoustic noise may be
generated by resonating the characteristic frequency which is determined by the dimensions of the
Capacitor.
As a measure to prevent this phenomenon, changing the size of the Capacitor is effective to change its
resonance frequency.
Also there is another measure changing the materials of the Capacitors to the Low-loss type, which has no
(or less) piezoelectricity, or to Class1.
which has no (or less) piezoelectricity, or to Class1 is also available.
(2) Vibration or impact applied to the Capacitors may cause noise because mechanical force is converted to
electrical signals (Especially, application to around the amplifier unit) .
As a measure to prevent this phenomenon, changing the materials of the Capacitor to the Low-loss type,
which has no (or less) piezoelectricity, or to Class1 is also available.
(3) Even if a whining sound is generated, there is no problem in product performance and reliability, however,
check the worrisome phenomenon which may generate noise in your equipment.
As a measure to prevent this phenomenon, changing to the Capacitor different in characteristics, size and
shape as shown in the (1), (2) above is effective.
As the other measures, changing the mounting direction of the Capacitors to bring under control the
resonance with equipment bodies such as printed circuit board, or the Capacitors are fixed with equipment
bodies such as printed circuit board by adhesive may be effective.
2- 2.Design of Printed Circuit Board
2-2-1. Selection of Printed Circuit Board
When the Capacitors are mounted and soldered on an Aluminum Substrate, the substrate has influences on
Capacitor’s reliabilities against “Temperature Cycles” and “Heat shock” because of difference in thermal
expansion coefficient between them.
It shall be carefully confirmed that the actual board applied does not deteriorate the characteristics of the
Capacitors.
Capacitance change vs. DC voltage
DC voltage (V)
Time (h)
Time (h)
Heat treatment
Under Ordinary Temperature Before and After Heat treatment