AP601
High Dynamic Range 1.8W 28V HBT Amplifier
2110-2170 MHz Application Note: Changing Icq Biasing Configurations
The AP601 can be configured to operate with lower bias current by varying the bias-adjust resistor – R2. The recommended
circuit configurations shown previously in this datasheet have the device operating with a 40 mA as the quiescent current (I
CQ
).
This biasing level represents the best tradeoff in terms of linearity and efficiency. Lowering I
CQ
will improve upon the
efficiency of the device, but degraded linearity. Increasing I
CQ
has nominal improvement upon the linearity, but will degrade
the device’s efficiency. Measured data shown in the plots below represents the AP601 measured and configured for 2.14 GHz
applications. It is expected that variation of the bias current for other frequency applications will produce similar performance
results.
Icq
(mA)
10
20
30
40
50
60
70
80
R2
(Ω)
12k
5.44k
3.48k
2.61k
2.06k
1.67k
1.42k
1.22k
V
PD
(V)
5
5
5
5
5
5
5
5
PIN_V
PD
(V)
2.50
2.58
2.63
2.68
2.72
2.77
2.81
2.85
GND
C7
1000pF
V
PD
Thermal Rise vs. Output Power vs. Icq
Vcc = 28V
80
10 mA
Thermal Rise (˚C)
60
40
20
0
14
20 mA
30 mA
40 mA
50 mA
60 mA
70 mA
80 mA
3,3pF
C22
1.2pF
C5
2.4pF
C19
1.8pF
16
18
20
22
24
26
Output Power (dBm)
ACLR1 vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 2140 MHz, 25
˚C
Efficiency vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 2140 MHz, 25
˚C
Efficiency vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 2140 MHz, 25
˚C
-30
120
30
Collector Efficiency (%)
Collector Current (mA)
10 mA
50 mA
20 mA
60 mA
30 mA
70 mA
40 mA
80 mA
10 mA
20 mA
60 mA
30 mA
70 mA
40 mA
80 mA
10 mA
30 mA
50 mA
70 mA
V
BIAS
20 mA
40 mA
60 mA
80 mA
100
80
60
40
20
0
50 mA
25
20
15
10
5
0
ACLR1 (dBc)
-40
-50
-60
18
20
22
24
26
18
20
22
24
26
18
20
V
CC
22
24
26
Average Output Power (dBm)
Gain vs. Output Power vs. Icq
CW tone, Vcc = 28V, 2140 MHz, 25
˚C
Average Output Power (dBm)
Output Power vs. Input Power vs. Icq
CW tone, Vcc = 28V, 2140 MHz, 25
˚C
Average Output Power (dBm)
Efficiency vs. Output Power vs. Icq
CW tone, Vcc = 28V, 2140 MHz, 25
˚C
15
34
60
Collector Efficiency (%)
10 mA
20 mA
40 mA
60 mA
80 mA
Output Power (dBm)
14
50
40
30
20
10
0
30
30 mA
50 mA
70 mA
Gain (dB)
13
12
11
10
18
22
26
30
34
10 mA
50 mA
20 mA
60 mA
30 mA
70 mA
40 mA
80 mA
26
10 mA
30 mA
20 mA
40 mA
60 mA
80 mA
22
50 mA
70 mA
18
4
8
12
16
20
18
22
26
30
34
Output Power (dBm)
Input Power (dBm)
Output Power (dBm)
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
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