AP603
High Dynamic Range 7W 28V HBT Amplifier
1930-1990 MHz Application Note: Changing Icq Biasing Configurations
The AP603 can be configured to be operated 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 160 mA as the
quiescent current (ICQ). This biasing level represents the best tradeoff in terms of linearity and efficiency. Lowering ICQ will
improve upon the efficiency of the device, but degraded linearity. Increasing ICQ has nominal improvement upon the linearity,
but will degrade the device’s efficiency. Measured data shown in the plots below represents the AP603 measured and
configured for 1.96 GHz applications. It is expected that variation of the bias current for other frequency applications will
produce similar performance results.
Thermal Rise vs. Output Power vs. Icq
Icq
R2
VPD PIN_VPD
Vcc = 28V
100
80
60
40
20
0
(mA) (Ω)
(V)
5
5
5
5
5
5
5
(V)
2.46
2.52
2.61
2.68
2.74
2.80
2.89
2.98
20 mA
20
40
80
120
160
200
260
320
4.32k
2.33k
1.24k
852
40 mA
80 mA
C7
120 mA
160 mA
200 mA
260 mA
320 mA
1000pF
W = .030”
L = 1.035”
649
L3
4.7 nH
521
100pF
100pF
C29
1.2pF
C5
3.3pF
C28
3.3pF
398
18
20
22
24
26
28
30
32
5
313
Output Power (dBm)
ACLR1 vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 1960 MHz, 25 ˚C
Icc vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 1960 MHz, 25 ˚C
Efficiency vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 1960 MHz, 25 ˚C
400
25
20
15
10
5
-35
20 mA
40 mA
-40
-45
-50
-55
-60
-65
80 mA
120 mA
200 mA
320 mA
300
200
100
0
160 mA
260 mA
20 mA
80 mA
160 mA
260 mA
40 mA
20 mA
80 mA
160 mA
260 mA
40 mA
120 mA
200 mA
320 mA
120 mA
200 mA
320 mA
0
22
24
26
28
30
32
22
24
26
28
30
32
22
24
26
28
30
32
Average Output Power (dBm)
Average Output Power (dBm)
Average Output Power (dBm)
Gain vs. Output Power vs. Icq
CW tone, Vcc = 28V, 1960 MHz, 25 ˚C
Output Power vs. Input Power vs. Icq
Efficiency vs. Output Power vs. Icq
CW tone, Vcc = 28V, 1960 MHz, 25 ˚C
CW tone, Vcc = 28V, 1960 MHz, 25 ˚C
14
13
12
11
10
9
38
50
20 mA
40 mA
80 mA
120 mA
200 mA
320 mA
40
30
20
10
0
34
30
26
22
160 mA
260 mA
20 mA
80 mA
160 mA
260 mA
40 mA
120 mA
200 mA
320 mA
20 mA
40 mA
80 mA
120 mA
320 mA
160 mA
200 mA
260 mA
22
26
30
34
38
10
14
18
Input Power (dBm)
IMD3 vs. Output Power vs. Icq
22
26
22
26
30
Output Power (dBm)
IMD5 vs. Output Power vs. Icq
34
38
Output Power (dBm)
OIP3 vs. Output Power vs. Icq
CW Two-tone signal, 1960 MHz, ∆f = 1 MHz, Vcc = 28V, 25 ˚C
CW Two-tone signal, 1960 MHz, ∆f = 1 MHz, Vcc = 28V, 25 ˚C
CW Two-tone signal, 1960 MHz, ∆f = 1 MHz, Vcc = 28V, 25 ˚C
55
-20
-30
-40
-50
-60
-20
20 mA
40 mA
80 mA
120 mA
320 mA
20 mA
40 mA
80 mA
120 mA
320 mA
160 mA
200 mA
260 mA
-30
-40
-50
-60
-70
-80
160 mA
200 mA
260 mA
50
45
40
35
30
20 mA
40 mA
80 mA
120 mA
320 mA
160 mA
200 mA
260 mA
26
28
30
32
34
36
26
28
30
32
34
36
26
28
30
32
34
36
Output Power, PEP (dBm)
Output Power, PEP (dBm)
Output Power, PEP (dBm)
Specifications and information are subject to change without notice
Page 8 of 14 May 2007 ver 1
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