CV210-3A
AMP1
INPUT
IF1
OUTPUT
GND
MIXER
IF/RF1
GND
28
N/C 1
GND 2
BIAS 3
GND 4
N/C 5
GND 6
N/C 7
8
GND
9
MIXER
IF/RF2
27
GND
26
25
24
23
GND
22
21 BIAS
The Communications Edge
TM
Product Information
Cellular-band Dual-Branch Downconverter
Device Architecture / Application Circuit Information
RF/IF
IF Amp 1
Typical Downconverter Performance Chain Analysis (Each Branch)
Stage
LO Amp / MMIC Mixer
IF Amplifier
CV210-3A
Gain
(dB)
Input
P1dB
(dBm)
Input
IP3
(dBm)
NF
(dB)
Current
(mA)
90
150
390*
Cumulative Performance
Input
Input
Gain
NF
P1dB
IP3
(dB)
(dB)
(dBm)
(dBm)
-8.0
17.0
32.6
8.3
10.3
10.0
29.0
10.3
10.3
+10.0
+29.0
10.3
20 GND
19 N/C
18 GND
LO Driver Amp
IF Amp 2
RF/IF
10
GND
11
AMP2
INPUT
12
GND
13
IF2
OUTPUT
14
GND
17 LO
16 GND
15 N/C
-8.0
17.0
32.6
8.3
18.3
3.0
23.5
2.1
Cumulative Performance
* The 2
nd
branch includes another mixer and IF amplifier, which increases the total current consumption
of the MCM to be 390 mA.
Printed Circuit Board Material:
.014” FR-4, 4 layers, .062” total thickness
CV210-3A:
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:
In a downconversion application, the incoming RF
signal impinges on the switching elements of the mixer; the interaction
with these switches produces a signal at the IF frequency. The two
signals (RF and IF) are directed to the appropriate ports by the external
diplexer. A four-element diplexer is used in the circuit implementation.
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.
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 6 February 2006
WJCI [ WJ COMMUNICATION. INC. ]
