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10-44
RF2637
Rev A5 050829
Application Schematic
Evaluation Board Schematic
(Download Bill of Materials from www.rfmd.com.)
1
2
3
4
8
7
6
5
GAIN
CONTROL
R1:
1 k
Ω
CDMA-
CDMA+
CDMA IF Filter
Z
S=500 Ω
Z
IN, EFF=500 Ω
Z
IN=1 kΩ
Z
S, EFF=333 Ω
Measurement
Reference Plane
L1
L1
V
CC
C2
OUT+
OUT-
V
CC
R2: 500
Ω
C1
C1
C2
Measurement
Reference Plane
Z
LOAD=500Ω
Z
LOAD,EFF=250 Ω
Z
OUT=500 Ω
10 nF
10 nF
R1 sets the CDMA balanced input impedance. The effective input impedance is then 500
Ω.
R2 sets the balanced output impedance to 500
Ω. L1 and C2 serve dual purposes. L1 serves
as an output bias choke, and C2 serves as a series DC block. In addition, the values of L1
and C2 may be chosen to form an impedance matching network of the load impedance is not
500
Ω. Otherwise, the values of L1 and C1 are chosen to form a parallel-resonant tank circuit
at the IF when the load impedance is 500
Ω.
GAIN
4.7 k
Ω
GAIN
CONTROL
R3
510
Ω
C8
15 pF
C9
15 pF
L3
390nH
L4
390nH
C6
10 nF
R2
4.7 k
Ω
T1
C3
15 pF
C1
10 nF
C4
15 pF
C2
10 nF
L1
390 nH
L2
390 nH
1
2
3
4
8
7
6
5
T2
C5
1 nF
50
Ω μstrip
J2
SMA
OUT
50
Ω μstrip
J1
SMA
CDMA
GC
VCC
2627400A
R1
1 k
Ω
VCC
C10
10 nF
C7
10 nF
1
2
3
P1
P1-1
P1-3
VCC
GND
GC
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