Information
3.2mm
Solder Ball
Solder balls reduce the creepage distance between
t
erminations and thus reduce the arcing voltage
Creepage distance v.s. Arcing Voltage
Recommended Solder Pad Design
Land
A
Solder Resistor
C
B
Capacitor
EIA Code
Chip (mm) Land (mm)
L W A B C
1808 4.6
0.3 2.0 0.2 3.2~3.6 1.2~2.4 1.5~1.8
1812 4.6 0.3 3.2 0.2 3.2~3.6 1.2~2.4 2.3~3.0
2208 5.7 0.4 2.0 0.2 4.0~4.6 1.2~2.4 1.5~1.8
2211 5.7 0.4 2.0 0.3 4.0~4.6 1.2~2.4 2.0~2.6
2220 5.7 0.4 5.0 0.4 4.0~4.6 1.2~2.4 3.5~4.8
The distance between terminations also has a direct effect on the arcing voltage. The greater the distance
(chip size) the higher this voltage will be. Solder pad design will have a significant effect on the arcing of
high voltage capacitors. Above is our recommended solder pad land design or each chip size.
Arc Prevention Coating.
The application of the Arc Prevention coating, which is a high insulation resistance material, coats the surface
of the dielectric with a smooth and non porous layer that prevents moisture entering the surface pours and also
aids cleaning post soldering. The following diagrams show the difference between coated and non coated X7R
components.
Item
Item
Porosity (x1000)
Porosity (x1000)
Before
Before
After
After
Surface Appearance
of non coated and
coated product.
Surface Comparison
Hi
gh Voltage Test Comparison
• T
he coating reduces the porosity of the X7R surface and provides a smooth surface which help prevent surface arcing.
• The maximum Hi-pot test level will be increased by >1000Vdc after coating with both unsoldered and soldered cpmponents.
Using the Holy Stone Arc Prevention coating increases the surface arcing voltage of X7R capacitors to almost
that of an equivalent NP0 part. However the higher dielectric constant of X7R allows for higher capacitance
values to be achieved in any given case size.
The Holy Stone Arc Prevention coating provides a total solution to the harmful effects of surface arcing.
High Voltage Test
0
10
20
30
40
50
60
70
100 1000 10000
Voltage (Vdc)
Failure Rate (%)
Normal Type
Coated Product
- 61 -
Coated Products for Surface Arc Prevention
Holy Stone