Selecting Evox Rifa Capacitors
for Pulse Applications
Begin with
the peak DC
application voltage
Pulse applications
For pulses with fast edges use this selector chart as a
guideline for capacitor selection.
The dV/dt figure at left is 1000 V/uS.
Capacitor dV/dt specifications are for
pulses equal to the capacitor
rated voltage. If the peak
pulse voltage is less than
0.2 uS
the capacitor rated voltage,
multiply the application dV/dt by the ratio of
Vpeak / Vrated. In this example using a 400VDC
capacitor the required dV/dt rating is
1000 V/uS x (200 Vpeak / 400 Vrated) = 500 V/uS.
≤ 1000 V
200 V
dV/dt
≤ 600
V/µS
≤ 2500 V/µS
DC
voltage
req’d
dV/dt figures are
approximate and depend
on the capacitance and
the amplitude of the
pulse compared to the
capacitor rated voltage.
See notes at left.
≤ 1000
V/µS
> 1000 V
dV/dt
≤ 25,000
V/µS
≤ 2500
V/µS
High frequency
Sinewave current
For continuous sinewave
applications it is only
necessary to check the ACRMS
current at the operating
frequency, not the dV/dt.
©2008 KEMET
Less AC
current
AC current capability
If the pulses are repetitive
on high frequency basis
the ACRMS current capability
of the capacitor must
also be checked at the
operating frequency. Go to
www.evoxrifa.com/n_america
and download the free
PCCad software.
PHE426
Single
metallized
PP
PFR
Film/foil
PP
SMD
SMD
GPC
Double
metallized
PEN
SPC
Double
metallized
PPS
PHE450
Double
metallized
PP
PHE450
Double
metallized
PP
(up to
630 VDC)
(1 and 2
section
depending
on
voltage)
(2 and 3
section
depending
on
voltage)
More AC
current
Datasheets are available at www.evoxrifa.com/n_america
PHE448
Film/Foil
2 section
PP