Precautions on the use of Axial Leaded Ceramic Capacitors
■PRECAUTIONS
1. Circuit Design
◆Verification of operating environment, electrical rating and performance
1. A malfunction in medical equipment, spacecraft, nuclear reactors, etc. may cause serious harm to human life or have severe social
ramifications. As such, any capacitors to be used in such equipment may require higher safety and/or reliability considerations and
should be clearly differentiated from components used in general purpose applications.
◆Verification of Rated voltage（ DC rated voltage）
1. The operating voltage for capacitors must always be lower than their rated values.
If an AC voltage is loaded on a DC voltage, the sum of the two peak voltages should be lower than the rated value of the capacitor
chosen. For a circuit where both an AC and a pulse voltage may be present, the sum of their peak voltages should also be lower than
the capacitor's rated voltage.
◆Self-generated heat (Verification of Temperature)
Precautions
1. If the capacitors specified only for DC use are used in AC or pulse circuits, the AC or a pulse current can generate heat inside the
capacitor so the self-generated temperature rise should be limited to within 20℃. The surface temperature measured should include
this self-temperature rise. Therefore, it is required to limit capacitor surface temperature including self -generated heat should not
exceed the maximum operating temperature of +85℃.
◆Operating Environment precautions
1. Capacitors should not be used in the following environments:
（1）Environmental conditions to avoid
a. exposure to water or salt water.
b. exposure to moisture or condensation.
c. exposure to corrosive gases (such as hydrogen sulfide, sulfurous acid, chlorine, and ammonia)
1-1. When an AC or a pulse voltage is applied to capacitors specified for DC use, even if the voltage is less than the rated voltage, the AC
current or pulse current running through the capacitor will cause the capacitor to self-generate heat because of the loss
characteristics.
The amount of heat generated depends on the dielectric materials used, capacitance, applied voltage, frequency, voltage waveform, etc.
The surface temperature changes due to emitted heat which differs by capacitor shape or mounting method.
Please contact Taiyo Yuden with any questions regarding emitted heat levels in your particular application. It is recommended the
temperature rise be measured in the actual circuit to be used.
1-2. For capacitors, the voltage and frequency relationship is generally determined by peak voltage at low frequencies, and by self-generated
heat at high frequencies. (Refer to the following curve.)
Technical
considerations
Sum of the peak voltage
（peak to peak）
Self-generated heat limit
Difference in
self-generated heat
relative to capacitance
Frequency
2. PCB Design
◆Design of the capacitor mount
1. When capacitors are mounted onto a PC board, hole dimensions on the board should match the lead pitch of the component, if not it will
Precautions
cause breakage of the terminals or cracking of terminal roots covered with resin as excess stress travels through the terminal legs. As
a result, humidity resistance performance would be lost and may lead to a reduction in insulation resistance and cause a withstand
voltage failure.
3. Considerations for automatic insertion
◆Adjustment Automatic Insertion machines（ leaded components）
Precautions
1. When inserting capacitors in a PC board by auto-insertion machines the impact load imposed on the capacitors should be minimized to
prevent the leads from chucking or clinching.
Technical
１. When installing products, care should be taken not to apply distortion stress as it may deform the products.
２. Our company recommends the method to place the lead with fewer loads that join the product.
considerations
4. Soldering
▶ This catalog contains the typical specification only due to the limitation of space. When you consider the purchase of our products, please check our specification.
For details of each product (characteristics graph, reliability information, precautions for use, and so on), see our Web site (http://www.ty-top.com/) .
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TAIYO YUDEN [ TAIYO YUDEN (U.S.A.), INC ]
