4

May 09, 2001

SAW Components

B3571

868,60 MHz

Low-loss Filter

Data Sheet

Matching network to 50

Ω (element values depend on pcb layout and equivalent circuit)

Minimising the crosstalk

For a good ultimate rejection a low crosstalk is necessary. Low crosstalk can be realised with

a good RF layout.

Grounding pins for input transducer are pin 1,3 and for output transducer 5,7. Close to those

pins via holes (through holes) should be placed to achieve a low impedance path to system

ground. If a grounding plane at the top side of the PCB is present, the grounding plane can be

connected to pin 1,3,5,7 at the top side too.

The optimised PCB layout, including matching network for transformation to 50 Ohm, is shown

here.

Optimised PCB layout for SAW filters in QCC8C package, pinning 2,6 (top side, scale 1:1)

The bottom side is a copper plane (system ground area).

For good contact of the upper grounding area with the lower side it is necessary to place

enough via holes.