TFS35F Datasheet, PDF (1/1 Pages) Vectron International, Inc – Application Note

Ltp: tft027
VI TELEFILTER
version 1.1
Application Note
TFS 35F
05.07.2007
1/1
1. General
The filter is driven in a single-ended way. It can be matched to 500 Ω on input and 1000 Ω on output
side.
The matching element values given below are only valid in theory. The matching elements have to be
optimised regarding the circuit and PCB design as well as existing parasites.
2. Theoretical matching
The termination impedances of the filter are:
source impedance:
310 Ω || - 25,7 pF
load impedance:
690 Ω || - 10,1 pF
The values of the matching elements given below are calculated from the source and load
impedances. If the values of the matching elements do not come up to standard values, the closest
standard values are given in brackets.
500 Ω / 1000 Ω test circuit
11
5
12 ^SAW
6
L1
L2
1, 2, 3, 4, 7, 8, 9, 10
L1 = 680 nH
L2 = 1800 nH
The matching on a PCB differs slightly from the theoretical matching due to parasites of the PCB.
If the parasites on the customer board (mentioned parasites, additional parasites of active parts)
differ from this PCB, the matching elements should be adjusted slightly.
Should you require more detailed information, please do not hesitate to contact us at
TELEFILTER GmbH
Potsdamer Straße 18
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.