Medium Power Film Capacitors
FFB (RoHS Compliant)
The FFB series uses a non-impregnated metallized
polypropylene or polyester dielectric with the controlled
self-healing process, specially treated to have a very high
dielectric strength in operating conditions up to 105°C.
The FFB has been designed for printed circuit board mount-
ing. Furthermore, their performances allow to be a very inter-
esting alternative to electrolytic technology because they
can withstand much higher levels of surge voltage.
APPLICATIONS
The FFB capacitor is particularly designed for DC filtering,
low reactive power.
HOT SPOT CALCULATION
See Hot Spot Temperature, page 3.
θhot spot = θambient + (Pd + Pt) x Rth
with Pd (Dielectric losses) = Q x tgδ0
1
Q x tgδ0 ⇒ [ ⁄
2
x Cn x (Vpeak peak)2 x f ] x tgδ0
to
tgδ0 (tan delta)
For polypropylene, tgδ0 = 2 x 10-4 for frequencies
up to 1MHz and is independent of temperatures.
For polyester, tgδ0 values are shown in graph 4
on page 3.
2
Pt (Thermal losses) = Rs x (Irms
)
where
Cn in Farad
V in Volt
Irms in Ampere
Rs in Ohm
f in Hertz
θ in °C
Rth in °C/W
PACKAGING MATERIAL
Self-extinguishing plastic case (V0 = in accordance with UL 94)
filled thermosetting resin.
WORKING TEMPERATURE
(according to the power to be dissipated) -55°C to +105°C
Self-extinguishing thermosetting resin (V0 = in accordance with
UL 94; I3F2 = in accordance with NF F 16-101).
LIFETIME EXPECTANCY
One unique feature of this technology (as opposed to elec-
trolytics) is how the capacitor reacts at the end of its lifetime.
Unlike aluminum, electrolytics film capacitors do not have a
catastrophic failure mode. Film capacitors simply experience
a parametric loss of capacitance of about 2%, with no risk of
short circuit.
STANDARDS
IEC 61071-1, IEC 61071-2: Power electronic capacitors
IEC 60384-16: Fixed metallized polypropylene
film dielectric DC capacitors
IEC 60384-16-1: Fixed metallized polypropylene
film dielectric DC capacitors
Please note that this is theoretical, however, as the capacitor
continues to be functional even after this 2% decrease.
Assessment level E
IEC 60384-17: Fixed metallized polypropylene
film dielectric AC and pulse
capacitors
IEC 60384-17-1: Fixed metallized polypropylene
film dielectric AC and pulse
capacitors
Assessment level E
IEC 60384-2: Fixed metallized polyester
capacitors
4