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

Matching switching

Part No.

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

Inductivity

Single

Symm.

Part No.

coil

coil

LP34-3

34

µH3 A

•

L20-7

20

µH7 A

•

LP20-7

20

µH7 A

•

LP183

2

∞ 183 µH8 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

Page

Description ....................................................................... 1

Filter Blocks FP Types ..................................................... 1

Page

Low-Loss Ring Core Chokes L/LP-Series ....................... 3

Mechanical Dimensions ................................................... 5