CV111-3A
UMTS-band High Linearity Downconverter
Device Architecture / Application Circuit Information
RF IN
GND
GND
MIXIF
GND
28
RF OUT 1
GND 2
N/C 3
GND 4
N/C 5
GND 6
MIXRF 7
8
GND
9
N/C
10
GND
11
MIXLO
27
26
25
24
23
22
21 IF OUT
GND
IF IN
IF
RF Amp
Typical Downconverter Performance Chain Analysis
Stage
RF Amplifier
RF Filter
LO Amp / MMIC Mixer
IF Amplifier
CV111-3A
Gain
(dB)
Output
P1dB
(dBm)
Output
IP3
(dBm)
NF
(dB)
Current
(mA)
140
---
80
140
360
Cumulative Performance
Output Output
Gain
NF
P1dB
IP3
(dB)
(dB)
(dBm)
(dBm)
12
21.0
41.0
3.5
10
19.0
39.0
3.6
1.5
6.1
22.2
4.8
20
20.7
37.9
5.4
20
20.7
37.9
5.4
IF Amp
20 GND
19 N/C
18 GND
LO Driver Amp
17 BIAS
16 GND
RF
LO
12
GND
13
LO OUT
14
GND
15 LO IN
12
21
41
3.5
-2
---
---
2.0
-8.5
8
23
9.1
18.5
23
41
2.1
Cumulative Performance
RF Amp Matching
RF Amp Bias
IF Amp Matching
IF 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)
CV111-3A:
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 / IF Amplifier Matching:
The RF amplifier requires a shunt
matching element for optimal gain and input return loss performance.
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.
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
products. The mixer performs the diplexing internally for the
CV111-3A; therefore the components shown in the diplexer section
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.
IF Amplifier Matching
Frequency (MHz)
L7 (nH)
C17 (pF)
R8 (ohms)
L4 (nH)
40
470
24
4.7
470
50
430
15
4.7
240
75
150
22
3.3
330
100
150
10
2.2
330
125
120
8.2
2.2
330
130
120
6.8
2.2
330
155
100
5.6
2.2
330
180
82
4.7
2.2
330
210
82
3.3
2.2
220
240
56
3.9
2.2
220
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 5 April 2007
WJCI [ WJ COMMUNICATION. INC. ]
