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
September 2004
The Communications Edge
TM
CV211-2
UMTS-band Dual-Branch Downconverter
Product Information
Device Architecture / Application Circuit Information
Typical Downconverter Performance Chain Analysis (Each Branch)
Cumulative Performance
Stage
Gain
(dB)
Input
P1dB
(dBm)
Input
IP3
(dBm)
NF
(dB)
Current
(mA)
Gain
(dB)
Input
P1dB
(dBm)
Input
IP3
(dBm)
NF
(dB)
LO Amp / MMIC Mixer
-9
11
30
9.3
80
-9
11
30
9.3
IF Amplifier
19
2
22
1.8
150
10
8
27.5
11
CV211-2
Cumulative Performance
380*
10
+8
+27.5
11
*
The 2
nd branch includes another mixer and IF amplifier, which increases the total current consumption
of the MCM to be 380 mA.
CV211-2: The application circuit can be broken up into three main
functions as denoted in the colored dotted areas above: RF/IF diplexing
(blue), IF amplifier matching (green), and dc biasing (purple). There are
various placeholders for chip components in the circuit schematic so that
a common PCB can be used for all WJ dual-branch converters. Further
details are given in the Application Note located on the website titled
“CV2xx Series - PWB Design Guidelines”.
External Diplexer: This is only used with the cellular-band CV
products.
The mixer performs the diplexing internally for the
CV211-2; therefore the components shown in the diplexer section
should be not be loaded except for L3, L10, L7, and L11, which
should contain a 0
Ω jumper.
IF Amplifier Matching:
The IF amplifier requires matching
elements to optimize the performance of the amplifier to the desired
IF center frequency. Since IF bandwidths are typically on the order
of 5 to 10%, a simple two element matching network, in the form of
either a high-pass or low-pass filter structure, is sufficient to match
the MMIC IF amplifier over these narrow bandwidths.
Proper
component values for other IF center frequencies can be provided by
emailing to applications.engineering@wj.com.
DC biasing: DC bias must be provided for the LO and IF amplifiers
in the converter. R1 sets the operating current for the last stage of the
LO amplifier and is chosen to optimize the mixer LO drive level.
Proper RF chokes and bypass capacitors are chosen for proper
amplifier biasing at the intended frequency of operation. The “+5 V”
dc bias should be supplied directly from a voltage regulator.
Printed Circuit Board Material:
.014” FR-4, 4 layers, .062” total thickness
1
2
3
4
5
6
7
21
20
19
18
17
16
15
28
27
26
25
24
23
22
8
9
10
11
12
13
14
IF Amp 2
IF Amp 1
LO Driver Amp
BIAS
GND
N/C
GND
LO
GND
N/C
RF 1
INPUT
GND
BIAS
GND
N/C
GND
IF
IF
RF
RF
RF 2
INPUT
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