Layout issues – Rainbow Electronics MAX2701 User Manual
Page 24
MAX2700/MAX2701
1.8GHz to 2.5GHz Direct Downconversion
Receivers
24
______________________________________________________________________________________
I/Q Mixer and VGA1
Output Load Requirements
To retain acceptable linearity performance, the mixer
and VGA1 output loads should be >600
Ω
.
Layout Issues
A properly designed PC board is an essential part of
any RF/microwave circuit. Use controlled impedance
lines on all frequency inputs and outputs. Use low-
inductance connections to ground on all ground pins
and wherever the components are connected to
ground. Place decoupling capacitors close to all V
CC
connections. For proper chip operation, the metal pad-
dle at the back of the chips must be grounded through
via holes in the board.
Table 2. MAX2700 LNA S-Parameters Low-Gain Mode (V
CC
= 3.0V)
Table 1. MAX2700 LNA S-Parameters High-Gain Mode (V
CC
= 3.0V)
FREQUENCY (GHz)
|S11|
∠
S11
|S21|
∠
S21
|S12|
∠
S12
|S22|
∠
S22
1.70
0.542
-84.1
7.09
53.97
0.023
65.36
0.367
37.3
1.75
0.485
-82.9
7.412
41.4
0.025
46.6
0.286
11.4
1.80
0.471
-80.1
7.268
29.5
0.024
34.3
0.216
-23.1
1.85
0.466
-78.8
7.07
19.9
0.0243
29.6
0.185
-68.4
1.90
0.443
-79.2
6.977
10.1
0.025
22.5
0.217
-99.5
1.95
0.441
-79.3
6.635
0.2
0.025
13.8
0.306
-127
2.00
0.436
-84.8
6.115
-7.96
0.024
16.4
0.387
-152.8
2.05
0.324
-88.3
6.119
-13.47
0.0338
15.23
0.408
-165
2.10
0.288
-74.9
5.947
-22.7
0.0383
-4.813
0.476
-176.7
2.15
0.300
-66.7
5.687
-31.1
0.0387
-20.7
0.529
172
2.20
0.320
-63.1
5.31
-40.5
0.0384
-32.8
0.587
162.4
FREQUENCY (GHz)
|S11|
∠
S11
|S21|
∠
S21
|S12|
∠
S12
|S22|
∠
S22
1.70
0.637
-65.6
0.731
52.5
0.018
77
0.398
41.5
1.75
0.625
-66.3
0.763
42.9
0.018
52
0.328
21.8
1.80
0.622
-67.1
0.772
31.3
0.016
40
0.258
-7
1.85
0.618
-67.3
0.76
21.2
0.014
39
0.191
-45
1.90
0.617
-67
0.758
10.3
0.014
38
0.203
-79
1.95
0.617
-69.2
0.717
-1.1
0.015
34
0.238
-114
2.00
0.616
-70.1
0.678
-10.7
0.014
24
0.332
-141
2.05
0.611
-71.8
0.603
-13
0.022
37.6
0.323
-105
2.10
0.611
-74.5
0.634
-19.5
0.028
13.4
0.36
-170
2.15
0.61
-76.8
0.634
0.27
0.03
-5
0.402
-178
2.20
0.6
-80
0.621
-37
0.033
-14
0.484
174