Specifications and information are subject to change without notice
WJ Communications, Inc
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Page 8 of 14 May 2007 ver 1
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.
Icq
(mA)
R2
()
VPD
(V)
PIN_VPD
(V)
20
4.32k
5
2.46
40
2.33k
5
2.52
80
1.24k
5
2.61
120
852
5
2.68
160
649
5
2.74
200
521
5
2.80
260
398
5
2.89
320
313
5
2.98
Thermal Rise vs. Output Power vs. Icq
Vcc = 28V
0
20
40
60
80
100
18
20
22
24
26
28
30
32
Output Power (dBm)
The
rma
lRi
se
(
C)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
V
BI
A
S
V
PD
GND
V
CC
C28
3.3pF
C7
1000pF
100pF
L3
C5
3.3pF
C29
1.2pF
100pF
W = .030”
L = 1.035”
4.7 nH
ACLR1 vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 1960 MHz, 25 C
-65
-60
-55
-50
-45
-40
-35
22
24
26
28
30
32
Average Output Power (dBm)
ACLR
1
(dBc
)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
Icc vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 1960 MHz, 25 C
0
100
200
300
400
22
24
26
28
30
32
Average Output Power (dBm)
Co
llecto
rCurrent
(mA)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
Efficiency vs. Output Power vs. Icq
WCDMA, Vcc = 28V, 1960 MHz, 25 C
0
5
10
15
20
25
22
24
26
28
30
32
Average Output Power (dBm)
Colle
ctor
Ef
ficien
cy
(%)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
Gain vs. Output Power vs. Icq
CW tone, Vcc = 28V, 1960 MHz, 25 C
9
10
11
12
13
14
22
26
30
34
38
Output Power (dBm)
Gain
(
dB)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
Output Power vs. Input Power vs. Icq
CW tone, Vcc = 28V, 1960 MHz, 25 C
22
26
30
34
38
10
14
18
22
26
Input Power (dBm)
Outp
u
tPo
wer
(d
Bm)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
Efficiency vs. Output Power vs. Icq
CW tone, Vcc = 28V, 1960 MHz, 25 C
0
10
20
30
40
50
22
26
30
34
38
Output Power (dBm)
Collec
tor
Eff
icienc
y
(%)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
OIP3 vs. Output Power vs. Icq
CW Two-tone signal, 1960 MHz, f = 1 MHz, Vcc = 28V, 25 C
30
35
40
45
50
55
26
28
30
32
34
36
Output Power, PEP (dBm)
OIP3
(
dBm)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
IMD3 vs. Output Power vs. Icq
CW Two-tone signal, 1960 MHz, f = 1 MHz, Vcc = 28V, 25 C
-60
-50
-40
-30
-20
26
28
30
32
34
36
Output Power, PEP (dBm)
IMD3
(
dBc)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA
IMD5 vs. Output Power vs. Icq
CW Two-tone signal, 1960 MHz, f = 1 MHz, Vcc = 28V, 25 C
-80
-70
-60
-50
-40
-30
-20
26
28
30
32
34
36
Output Power, PEP (dBm)
IMD5
(
dBc)
20 mA
40 mA
80 mA
120 mA
160 mA
200 mA
260 mA
320 mA