The Communications Edge TM
FP31QF
2-Watt HFET
Product Information
Reference Design: 3500 MHz
The application circuit is matched for output power.
Typical RF Performance
Measured S-Parameters
15
10
5
Drain Bias = +9 V, Ids = 450 mA, 25 °C
Frequency
MHz
dB
3500
11.9
-16
S21 – Gain
S11 – Input Return Loss
S22 – Output Return Loss
Output P1dB
dB
0
DB(|S[1,1]|)
DB(|S[2,1]|)
DB(|S[2,2]|)
dB
-8.8
-5
dBm
+33.5
-10
-15
-20
-25
Output IP3
(+18 dBm / tone, 1 MHz spacing)
dBm
+45
The 3.5 GHz Reference Circuit is shown for design purposes only. An
evaluation board is not readily available for this application. The reader can
obtain any FP31QF evaluation board and modify it with the circuit shown to
achieve the performance shown in this reference design.
3.3
3.35
3.4
3.45
3.5
3.55
3.6
3.65
3.7
Frequency (GHz)
Bill of Materials
Ref. Desig.
Value
22 pF
Part style
Size
C1, C4, C8, C10
C2
C3
Chip capacitor
Chip capacitor
Chip capacitor
Chip capacitor
Chip capacitor
0603
0603
0603
0603
1206
0805
0603
0603
0603
QFN 6x6
0.9 pF
1.0 pF
1000 pF
0.1 µF
6.8 nH
3.3 nH
2.2 Ω
C7, C11
C12
L1, L2
L3
Wirewound chip inductor
Multilayer chip inductor
Chip resistor
R1
R2
C3
50 Ω
FP31QF
Chip resistor
WJ 2W HFET
Do Not Place
C2
Q1
C5, C6
•
Both the C2 and C3 placements are between the first and second via locations
along the main microstrip line leading from the FP31QF device. Further
descriptions are shown in the diagram on the left.
•
•
•
The via hole spacing along the main microstrip line is .040”.
The distance from the edge of the FP31QF to the closer edge of L3 is .305”.
The transmission line lengths shown in the schematic are from the FP31QF
device edge to the component edge.
Circuit Board Material: .014” FR-4 (εr = 4.6),
4 layers (other layers added for rigidity), .062” total thickness, 1 oz copper
The main microstrip line has a line impedance of 50 Ω.
ID=C8
C=22 pF
ID=C7
C=1000 pF
Vds=9V @ 450 mA
ID=C11
C=1000 pF
-Vgg
ID=C12
C=1e4 pF
ID=R2
R=51 Ohm
ID=C10
C=22 pF
ID=L2
L=6.8 nH
ID=L1
L=6.8 nH
NET="FP31QF"
TLIN
ID=R1
R=2.2 Ohm
Z0=50 Ohm
EL=55 Deg
F0=3.5 GHz
2
ID=L3
L=3.3 nH
ID=C1
C=22 pF
ID=C4
C=22 pF
1
TLIN
TLIN
Z0=50 Ohm
EL=5.9 Deg
F0=3.5 GHz
Z0=50 Ohm
EL=12.8 Deg
F0=3.5 GHz
ID=C2
C=0.9 pF
ID=C3
C=1 pF
Specifications and information are subject to change without notice
Page 10 of 12 October 2006
WJ Communications, Inc • Phone 1-800-WJ1-4401 • FAX: 408-577-6621 • e-mail: sales@wj.com • Web site: www.wj.com
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