The Communications Edge TM
CV111-1A
PCS/DCS-band High Linearity Downconverter
Product Information
Device Architecture / Application Circuit Information
28
27
26
24
23
22
25
Typical Downconverter Performance Chain Analysis
RF OUT
GND
N/C
1
2
3
4
5
6
7
IF
21 IF OUT
Cumulative Performance
IF Amp
Output Output
GND
N/C
RF Amp
20
19
18
17
16
15
Gain
(dB)
NF
(dB)
Current
(mA)
Output Output
Stage
P1dB
IP3
Gain
(dB)
NF
(dB)
P1dB
(dBm)
21.0
19.0
6.1
IP3
(dBm)
41.0
39.0
22.2
37.9
(dBm)
(dBm)
GND
N/C
GND
BIAS
GND
LO IN
LO Driver Amp
RF Amplifier
RF Filter
LO Amp / MMIC Mixer
IF Amplifier
12
-2
-8.5
18.5
21
---
8
41
---
23
41
3.5
2.0
9.1
2.1
140
---
80
12
10
1.5
20
3.5
3.6
4.8
5.4
GND
MIXRF
RF
23
140
20.7
LO
CV111-1A
Cumulative Performance
360
20
20.7
37.9
5.4
8
9
10
12
13
14
11
IF Amp Matching
RF Amp Matching
IF Amp Bias
RF Amp Bias
RF Bandpass Filter /
Attenuator Pad
Printed Circuit Board Material:
.014” FR-4, 4 layers, .062” total thickness
LO Amp Bias
LO Amp Bias
RF / IF Diplexer
(used for cellular versions only)
CV111-1A: The application circuit can be broken up into four main
functions as denoted in the colored dotted areas above: RF/IF
diplexing (purple; this is only used with the cellular-band CV
products), amplifier matching (green), filtering (red), and dc biasing
(blue). There are various placeholders for chip components in the
circuit schematic so that a common PCB can be used for all WJ
single-branch converters. Additional placeholders for other optional
functions such as filtering are also included.
RF Bandpass Filtering: Bandpass filtering is recommended to
achieve the best noise figure performance with the downconverter.
The bandpass filter, implemented with a SAW filter on the
application circuit, allows for the suppression of noise from the
image frequency. It is permissible to not use a filter and use a 2 dB
pad with R6, R7, and R16 instead with slightly degraded noise
figure performance.
External Diplexer: This is only used with the cellular-band CV
RF / IF Amplifier Matching: The RF amplifier requires a shunt
products. The mixer performs the diplexing internally for the
matching element for optimal gain and input return loss performance. CV111-1A; therefore the components shown in the diplexer section
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.
should be loaded as follows: C2 = C14 = 0 Ω.
DC biasing: DC bias must be provided for the RF, 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 4 May 2006
WJCI [ WJ COMMUNICATION. INC. ]
