leaded_c_reli-PRP15 leaded_c_reli_e-01
■ PRECAUTIONS
* 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/) or CD catalogs.
1. Circuit Design
Precautions
◆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)
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)
Technical
consider-
ations
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.)
2. PCB Design
Precautions
◆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 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
Precautions
◆Adjustment Automatic Insertion machines (leaded components)
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
consider-
ations
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.
4. Soldering
Precautions
◆Selection of Flux
1. When soldering capacitors are on the board, flux should be applied thinly and evenly.
2. Flux used should be with less than or equal to 0.1 wt% (equivalent to Chroline) of halogenated content. Flux having a strong acidity content should not be applied.
3. When using water-soluble flux, special care should be taken to properly clean the boards.
◆Wave Soldering
1. Temperature, time, amount of solder, etc. are specified in accordance with the following recommended conditions.
2. Do not immerse the entire capacitor in the flux during the soldering operation. Only solder the lead wires on the bottom of the board.
◆Recommended conditions for using a soldering iron:
1. Put the soldering iron on the land-pattern.
Soldering iron's temperature - below 350℃
Duration - 3 seconds or less
Numbers of times - 1 times
The soldering iron should not directly touch the capacitor.
Technical
consider-
ations
◆Selection of Flux
1.
Flux is used to increase solderability in wave soldering, but if too much is applied, a large amount of flux gas may be emitted and may detrimentally affect
solderability. To minimize the amount of flux applied, it is recommended to use a flux-bubbling system.
2. With too much halogenated substance (Chlorine, etc.) content is used to activate the flux, an excessive amount of residue after soldering may lead to corrosion of the
terminal electrodes or degradation of insulation resistance on the surface of the capacitors.
3.
Since the residue of water-soluble flux is easily dissolved by water content in the air, the residue on the surface of capacitors in high humidity conditions may cause a
degradation of insulation resistance and therefore affect the reliability of the components. The cleaning methods and the capability of the machines used should also
be considered carefully when selecting water-soluble flux.
◆Wave Soldering
1. If capacitors are used beyond the range of the recommended conditions, heat stresses may cause cracks inside the capacitors, and consequently degrade the
reliability of the capacitors.
2. When the capacitors are dipped in solder, some soldered parts of the capacitor may melt due to solder heat and cause short-circuits or cracking of the ceramic
material. Deterioration of the resin coating may lower insulation resistance and cause a reduction of withstand voltage.
◆Recommended conditions for using a soldering iron:
1.If products are used beyond the range of the recommended conditions,heat stress may deform the products,and consequently degrade the reliability of the products.