Accessories
Filter & Ring Core Chokes FP L and LP Series
REV. SEP 29, 2003
Page 1 of 5
Description
These Filters and chokes are designed to reduce input in-
terference and/or output ripple voltages occurring in appli-
cations with switched mode power supplies. Since all our
filters contain a Moly Permalloy Powder (MPP) ring core
they feature very low DC losses as well as high DC mag-
netisation and operate perfectly at the input and/or output
of switching regulators ensuring effective filtering even at
elevated DC current levels. These special characteristics
allow the chokes to be operated at DC currents which con-
siderably exceed the rated current, by accepting a corre-
sponding gradual loss of inductance (unlike ferrite core
chokes where inductance rapidly decreases above a cer-
tain DC magnetising level).
In applications where switching regulators have long supply
lines, filters and chokes are used in order to prevent oscilla-
tions caused by their negative input impedance. For further
information refer also to switching regulator data for "Option
L", and to section: Technical Information: Installation & Ap-
plication
Table 1a: Type survey of FP filter blocks
Filter type
Part No.
Matching switching
regulator type
FP38
PSR 54
PSA 55
PSA 5A2
PSA 5A5
PSA 123
PSA 153
FP80
PSR 53
PSR 122.5
PSR 152.5
PSR 242
PSR 362
PSA 242.5
FP144
PSA 121.5
PSA 151.5
PSA 241.5
PSA 361
PSA 481
Table 1b: Type survey ring core chokes
Type
Part No.
Inductivity
I
Ln
Single
coil
Symm.
coil
LP34-3
34
μ
H
20
μ
H
20
μ
H
2
∞
183
μ
H
3 A
L20-7
7 A
LP20-7
7 A
LP183
8 A
Filter Blocks FP Types
The filter blocks contain, in addition to a MPP ring core, a
capacitor and an attenuation resistor, capable of handling
the high ripple currents seen at the input of switching regu-
lators. This forms a complete external filter system opti-
mised to prevent oscillations and to reduce superimposed
interference voltages and currents, specially designed for
use in PCB applications together with switching regulators
in an A01 case size. For selection of filters refer to the type
survey.
Table of Contents
Description ....................................................................... 1
Filter Blocks FP Types ..................................................... 1
Page
Page
Low-Loss Ring Core Chokes L/LP-Series ....................... 3
Mechanical Dimensions ................................................... 5