Aluminum Electrolytic Capacitor
1.3 Common Application Conditions to Avoid
The following misapplication load conditions will cause rapid deterioration to capacitor electrical p a ra m e t e r s. ln addition, rapid heating and gas generation within the capacitor can occur causing the pressure relief vent to operate and resuItant leakage of electrolyte. Under extreme conditions, explosion and fire could result. Leakinq electrolyte is combustible and electrically conductive.
(1) Reverse Voltaqe
DC capacitors have polarity. Verify correct polarity before insertion. For circuits with changing or uncertain polarity,use DC bipolar capacitors. DC bipolar capacitors are not suitable for use in AC circuits.
(2) Charqe/Discharqe Applications
Standard capacitors are not suitable for use in repeating charge/discharge applications. For charqe/discharqe applications consult us and advise actual conditions.
(3) Overvoltage
Do not appIy voltaqes exceeding the maximum specified rated voltages. Voltage up to the surge voltage rating are acceptable for short periods of time. Ensure that the sum of the DC voltage and the superimposed AC ripple voltage does not exceed the rated voltage.
(4) Ripple Current
Do not apply ripple currents exceeding the maximum specified value. For high ripple current applications, use a capacitor designed for high rippIe currents or contact us with your requirements.
Ensure that allowable ripple currents superimposed on low DC bias voltages do not cause reverse voltage conditions.
1.4Using Two or More Capacitors in Series or Parallel
(1) Capacitors Connected in Parallel
The circuit resistance can closely approximate the series resistance of the capacitor causing an imbalance of ripple current loads w i t h in the capacitors. Careful design of wiring methods can minimize the possibility of excessive ripple currents applied to a capacitor.
(2) Capacitors Connected in Series
The vinyl sleeve of the capacitor can be damaged i f s o l d e r p a s s e s t h r o u g h a l e a d h o l e fo r subsequently processed parts. Special care when locating hole positions in proximity to capacitors is recommended.
(3) Circuit Board Hole Spacing
The circuit board holes spacing should match the capacitor lead wire spacing within the specified tolerances. Incorrect spacing can cause excessive lead wire stress during the insertion process. This may resuIt in premature capacitor failure due to short or open circuit, increased leakage current, or electrolyte leakage.
(4)Land/Pad Pattern
The circuit board land/pad pattern size for chip capacitors is specified in the following table.
[ Table of Board Land Size vs. Capacitor Size ]
c |
|
|
|
b | a | b | Board land part |
|
|
| (mm) |
Size | a | b | c |
A(φ3) | 0.6 | 2.2 | 1.5 |
B(φ4) | 1.0 | 2.5. | 1.6 |
C(φ5) | 1.5 | 2.8 | 1.6 |
D(φ6.3) | 1.8 | 3.2 | 1.6 |
E(φ8 x 6.2L) | 2.2 | 4.0 | 1.6 |
F(φ8 x 10.2L) | 3.1 | 4.0 | 2.0 |
G(φ10 x 10.2L) | 4.6 | 4.1 | 2.0 |
Among others, when the size a is wide , back fillet can not be made, decreasing fitting strength.
❉Decide considering mounting condition, solderability and fitting strength, etc. based on the design standards of your company.
Normal DC leakage current differences among capacitors can cause voltage imbalances. The use of voltage divider shunt resistors with consideration to leakage currents, can prevent capacitor voltage imbaIances.
1.5Capacitor Mounting Considerations
(1) DoubIe - Sided Circuit Boards
Avoid wiring Pattern runs which pass between the mounted capacitor and the circuit board. When dipping into a solder bath, excess solder may collect under the capacitor by capillar y action and shortcircuit the anode and cathode terminals.
(2) Circuit Board Hole Positioning
Design, Specifications are subject to change without notice. Ask factory for technical specifications before purchase and/or use. Whenever a doubt about safety arises from this product, please inform us immediately for technical consulation without fail.
– EE18 –
Mar. 2005
