TFS380K Datasheet, PDF (1/1 Pages) Vectron International, Inc – Application Note

Ltp: tft031
VI TELEFILTER
version 1.1
Application Note
General
The filter is balanced driven. It is matched to 100 Ω
TFS 380K
21.09.2004
1/1
Theoretical matching
The balanced driven source and load impedances of the filter are:
Source impedance:
420 Ω || - 3,9 pF
Load impedance:
490 Ω || - 3,5 pF
The values of the matching elements, which are given below, are calculated from the source and load impedance.
If the values of the matching elements are not equal to standard values the best standard values are given in
brackets.
L1 = L2 = 29 nH
C1 = 13,8 pF
1
5
L1
C1
L2
2
SAW ₆
L3 = L4 = 30,3 nH
C2 = 12,8 pF
3, 4, 7, 8
L
C
L
Matching on the PCB
- matching on Telefilter-board (balanced driven, 50 Ohm):
L1 = 33 nH
L2 = 18 nH
C1 = 18 pF
L3 = 22 nH
L4 = 22 nH
C2 = 18 pF
The matching on the PCB does slightly differ from the theoretical matching. The reasons for
that are parasites of the PCB.
If the parasites on the customer board (mentioned parasites, additional parasites of active
parts) are different to this PCB the matching elements have to be slightly adjusted.
In case of questions please contact us to
TELEFILTER GmbH
Potsdamer Straße18
D 14 513 TELTOW / Germany
Tel: [phone] / Fax: [phone]
E-mail: [e-mail]
VI TELEFILTER reserves the right to make changes to the product(s) and/or information contained herein without notice. No liability is
assumed as a result of their use or application. No rights under any patent accompany the sale of any such product(s) or information.