Ltp: tft029

version 1.2

04.06.03

Application Note

TFS 210G

1/2

TELEFILTER GmbH

Potsdamer Straße 18

D 14 513 TELTOW / Germany

Tel: (+49) 3328 4784-0 / Fax: (+49) 3328 4784-30

E-Mail:

tft@telefilter.com

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.

1. General

The filter is single ended driven. It is matched to 50

Ω.

The matching element values given below are valid on the test PCB. If the parasitics on the

customer PCB and on this PCB are different, the matching elements have to be optimised

regarding the circuit and PCB design.

The matching elements have been chosen from the E12- series (European standard series

with fixed tolerances).

2. Theoretical matching

The termination impedances of the filter are:

source impedance:

860

Ω || - 6,4 pF

load impedance:

1160

Ω || - 6,7 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.

50

Ω test circuit

L2

Output

50 Ohm

C2

Input

50 Ohm

C1

L1

SAW

2,3,4,5,7,8,9,10

6

1

L1 = 100,8 nH

L2 = 96,4 nH

C1 =

30 pF

C2 = 33,8 pF