TFS211C_03 Datasheet, PDF (1/2 Pages) Vectron International, Inc – Application Note

Ltp: tft028
VI TELEFILTER
version 2.0
Application Note
TFS 211C
16.06.2003
1/2
1. General
The filter is symmetrical, i.e. input and output are exchangeable with each other.
The filter shall be driven single ended. If it is intended to the filter in an balanced environment this can be
supported as well. Please contact us for details.
The terminating impedances are :
1100 Ω || - 5.1 pF for the input
1100 Ω || - 5.2 pF for the output
This impedance is equal for the input and the output. It has to be realized at the point were the filter is mounted.
To match this impedance to the impedance of the system a matching circuit is required.
The terminating impedances depend on parasitics and q-values of matching elements and the board used, and are
to be understood as reference values only. Should there be additional questions do not hesitate to contact our
design team.
2. Theoretical matching
The values of the matching elements which are given below are calculated from the terminating impedances.
Because these are theoretical values they have to be modified on PCB’s corresponding to the existing parasitics.
50 Ohm test circuit
L1
10
5
L2
L3
SAW
L4
L1 = L2 = 164 nH
L3 = L4 = 180 nH
1, 2, 3, 4, 6, 7, 8, 9
TELEFILTER GmbH
Potsdamer Straße 18
D 14 513 TELTOW / Germany
Tel: [phone] / Fax: [phone]
E-Mail: [e-mail]
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