AH312
The Communications Edge
TM
Product Information
2 Watt, High Linearity InGaP HBT Amplifier
Application Note: Reduced Bias Configurations
The AH312 can be configured to be operated with lower bias current by varying the bias-adjust resistor – R1. The
recommended circuit configurations shown previously in this datasheet have the device operating in Class A operation.
Lowering the current has little effect on the gain, OIP3, and P1dB performance of the device, but will slightly lower the
ACLR/ACPR performance of the device as shown below. An example of the measured data below represents the AH312
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.
AH312-S8PCB2140 Performance Data
R1
(ohms)
15
22
43
62
110
Icq
(mA)
800
700
600
500
400
Pdiss
(W)
4.0
3.5
3.0
2.5
2.0
P1dB
(dBm)
+33.3
+33.3
+33.1
+33.0
+32.9
OIP3
(dBm)
+51.4
+50.9
+50.9
+50.7
+47.3
2.14GHz Gain vs. Output Power
10.2
55
2.14GHz OIP3 vs. Output Power per Tone
9.8
50
9.4
OIP3 (dBm)
Gain (dB)
Idq=800mA 'Class A'
9
45
Idq=800mA 'Class A'
Idq=700mA
Idq=700mA
Idq=600mA
8.6
40
Idq=600mA
Idq=500mA
Idq=500mA
Idq=400mA
35
18
20
22
24
26
28
30
32
34
10
8.2
Idq=400mA
12
14
16
18
20
22
24
Output Power (dBm)
W-CDMA ACLR vs. Output Channel Power
3GPP W-CDMA, Test Model 1 + 64 DPCH, ±5 MHz offset
Power Out per Tone (dBm)
CW PAE vs. Output Power
100
-35
Idq=800mA 'Class A'
Idq=800mA 'Class A'
Idq=700mA
Idq=600mA
Idq=700mA
-40
PAE (%)
Idq=600mA
ACLR (dBc)
-45
-50
-55
-60
-65
14
Idq=500mA
Idq=400mA
Idq=500mA
Idq=400mA
10
1
16
18
20
22
24
26
18
20
22
24
26
28
30
32
W-CDMA Channel Power Out (dBm)
CW Tone Power Out (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
Page 6 of 7 March 2006
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