B39431-B3567-U310 EPCOS Inc, B39431-B3567-U310 Datasheet - Page 4

• Manufacturer Part Number: B39431-B3567-U310
• Manufacturer: EPCOS Inc

Specifications of B39431-B3567-U310

• Saw Filter Type: Low-Loss Filter
• Center Frequency: 433.42MHz
• Insertion Loss: 4.8dB
• Pass Band Ripple (db): 3dB
• Termination Impedance: 50Ohm
• Package Type: QCC8C
• Case Height: 1.35mm
• Case Length: 5mm
• Case Depth: 5mm
• Mounting: Surface Mount
• Pin Count: 8
• Operating Temp Range: -35C to 85C
• Lead Free Status / RoHS Status: Compliant

Data Sheet
Matching network to 50
SAW Components
Low-loss Filter
Minimising the crosstalk
For a good ultimate rejection a low crosstalk is necessary. Low crosstalk can be realised with
a good RF layout. The major crosstalk mechanism is caused by the “ground-loop” problem.
Grounding loops are created if input-and output transducer GND are connected on the top-side
of the PCB and fed to the system grounding plane by a common via hole. To avoid the common
ground path, the ground pin of the input- and output transducer are fed to the system ground
plane (bottom PCB plane) by their own via hole. The transducers’ grounding pins should be
isolated from the upper grounding plane.
A common GND inductivity of 0.5nH degrades the ultimate rejection (crosstalk) by 20dB.
The optimised PCB layout, including matching network for transformation to 50 Ohm, is shown
here. In this PCB layout the grounding loops are minimised to realise good ultimate rejection.
Optimised PCB layout for SAW filters in QCC8C package, pinning 2,5 (top side, scale 1:1)
The bottom side is a copper plane (system ground area). The input and output grounding pins
are isolated and connected to the common ground by separated via holes.
For good contact of the upper grounding area with the lower side it is necessary to place
enough via holes.
(element values depend on pcb layout and equivalent circuit)
4
May 09, 2001
L
L
L
s1
s2
k
= 47 nH
= 39 nH
= 47 nH
433,42 MHz
B3567