VG112
The Communications Edge
TM
Product Information
PCS/UMTS-band Variable Gain Amplifier
2140 MHz Application Circuit Performance
Performance using the circuitry on the VG112-PCB Evaluation Board
Circuit Board Material: .014” FR-4, 4 layers, .062” total thickness
•
The center of C5 should be placed 5mm (.197”) away from the edge of the VG112.
•
The input trace is a high impedance line and is needed to get a good input match into the VGA.
•
The board is optimized for performance at 2140 MHz. Performance at 1960 MHz can be
optimized by replacing C5 with 2.7 pF at location A on the WJ VG112 evaluation board.
Bill of Materials
Ref. Des. Description
C1, C7, C10 47 pF Chip Capacitor
C2, C3, C4,
1000 pF Chip Capacitor
C8, C9
C5
2.4 pF Chip Capacitor
C6
3.3
μF
Chip Capacitor
L1, L2
18 nH Chip Inductor
R1
220
Ω
Chip Resistor
R3
75
Ω
Chip Resistor
R2, R4
0
Ω
Chip Resistor
U1
VG112-G VGA
Size
0603
0603
0603
0805
0603
0603
0603
0603
QFN 6x6
S21 vs. Frequency
Vctrl=0V (Maximum Gain Setting)
S11 vs. Frequency
Vctrl=0V (Maximum Gain Setting)
S22 vs. Frequency
Vctrl=0V (Maximum Gain Setting)
28
26
S 2 1 (d B )
S 1 1 (d B )
0
0
-40 °C
+25 °C
+85 °C
-5
-5
S 2 2 (d B )
-10
-15
-20
-40 °C
+25 °C
+85 °C
24
22
20
-40 °C
+25 °C
+85 °C
-10
-15
-20
-25
1800
18
1800
1900
2000
Frequency (MHz)
2100
2200
1900
2000
Frequency (MHz)
2100
2200
-25
1800
1900
2000
Frequency (MHz)
2100
2200
S21 vs. Frequency vs. Control Voltage
S11 vs. Frequency vs. Control Voltage
S22 vs. Frequency vs. Control Voltage
30
20
S 1 1 (d B )
S 2 1 (d B )
10
0
Vctrl=0.00V
Vctrl=1.52V
Vctrl=0.73V
Vctrl=2.20V
Vctrl=1.06V
Vctrl=4.50V
0
-5
-10
-15
-20
-25
1800
Vctrl=0.00V
Vctrl=1.52V
Vctrl=0.73V
Vctrl=2.20V
Vctrl=1.06V
Vctrl=4.50V
0
-5
S 2 2 (d B )
-10
-15
-20
-25
1800
Vctrl=0.00V
Vctrl=1.52V
Vctrl=0.73V
Vctrl=2.20V
Vctrl=1.06V
Vctrl=4.50V
-10
1800
1900
2000
Frequency (MHz)
2100
2200
1900
2000
Frequency (MHz)
2100
2200
1900
2000
Frequency (MHz)
2100
2200
Specifications and information are subject to change without notice
WJ Communications, Inc
•
Phone 1-800-WJ1-4401
•
FAX: 408-577-6621
•
e-mail: sales@wj.com
•
Web site: www.wj.com
Page 2 of 4
May 2006
WJCI [ WJ COMMUNICATION. INC. ]
