Document Number: 28155 For technical questions, contact: RFI@vishay.com
www.vishay.com
Revision: 22-Dec-10 11
MKT334
Series Impedance Film Capacitors
Radial Potted Type
Vishay BCcomponents
APPLICATION NOTES
• These capacitors are suitable for the application as voltage-division impedance in series with the mains (50 Hz/60 Hz) with a
maximum mains voltage of U
RAC
.
• For capacitors connected in parallel, normally the proof voltage and possibly the rated voltage must be reduced. For information
depending of the capacitance value and the number of parallel connections contact: dc-film@vishay.com
• These capacitors are not suitable for mains applications as across-the-line capacitors without additional protection, as
described under item 7. These mains applications are strictly regulated in safety standards and therefore
electromagnetic interference suppression capacitors conforming the standards must be used.
• The peak voltage (U
p
) shall not be greater than the permissible DC voltage (U
RDC
).
• The peak-to-peak voltage (U
p-p
) shall not be greater than 2 √2 x U
RAC
to avoid the ionization inception level.
• The voltage peak slope (dU/dt) shall not exceed the rated voltage pulse slope in an RC-circuit at rated voltage and without
ringing. If the pulse voltage is lower than the rated DC voltage, the rated voltage pulse slope may be multiplied by U
RDC
and
divided by the applied voltage.
For all other pulses following equation must be fulfilled:
• T is the pulse duration
• The rated voltage pulse slope is valid for ambient temperatures up to 105 °C.
• The maximum component surface temperature must be lower than 105 °C.
• Since in circuits used at voltages over 280 V peak-to-peak the risk for an intrinsically active flammability after a capacitor
breakdown (short circuit) increases, it is recommended that the power to the component is limited to 100 times the values
mentioned in the table: “Heat conductivity”. This is normally fulfilled by the impedance of the device in series with capacitor or
by an additional resistor.
HEAT CONDUCTIVITY (G) AS A FUNCTION OF (ORIGINAL) PITCH AND CAPACITOR BODY THICKNESS IN mW/°C
rated
T
dt
dU
()
dt
dU
()
∫
2
0
x dt < U
RDC
x
2 x
W
max.
(mm)
HEAT CONDUCTIVITY (mW/°C)
Pitch 10 mm Pitch 15 mm Pitch 22.5 mm Pitch 27.5 mm
4.06.0---
4.5----
5.0 7.5 10 - -
6.0 9.0 11 19 -
7.0 - 12 21 -
8.5 - 16 25 -
9.0 - - - 30
10.0- 182833
11.0 - - - 36
12.0 - - 31 -
13.0 - - - 42
15.0 - - - 48
18.0 - - - 57
