Design Application Note - AN-079 SGA-8543Z Amplifier Application Circuits

Design Application Note - AN-079
SGA-8543Z Amplifier Application Circuits
Abstract
RFMD SGA-8543Z is a high performance
SiGe amplifier designed for operation from 50 MHz to 3.5
GHz. This application note illustrates application circuits
for the 880 MHz and 2440 MHz frequency bands.
Introduction
The application circuits were designed to achieve the
optimum combination of NF, P1dB, and OIP3, while
maintaining flat gain and reasonable return losses.
Special consideration was given to insure amplifier stability
at low frequencies, where the device exhibits high gain.
These designs were created to illustrate the general
performance capabilities of the device under CW
conditions. Users may wish to modify these designs to
achieve optimum performance under specific input
conditions and system requirements.
All recommended components are standard values
available from well-known manufacturers. Components
specified in the bill of materials (BOM) have known
parasitics which in some cases are critical to the circuit’s
performance. Deviating from the recommended BOM may
result in a performance shift due to varying parasitics.
Matching component placement is critical to each circuit’s
performance.
Circuit Details
RFMD will provide the detailed layout (AutoCad format) to
users wishing to use the exact same layout and substrate
material shown in the following circuits. The circuits
recommended within this application note were designed
using the following PCB stackup:
Design Considerations and Trade-offs
-Biasing Techniques
All HBT amplifiers are subject to device current variation due
to the decreasing nature of the internal VBE with increasing
temperature. In the absence of an active bias circuit or
resistive feedback, the decreasing VBE will result in
increased base and collector currents. As the collector
current continues to increase under constant VCE conditions
the device may eventually exceed its maximum dissipated
power limit resulting in permanent device damage. The
designs included in this application note contain passive
bias circuits that stabilize the device current over
temperature and desensitize the circuit to device process
variation.
The passive bias circuits used in these designs include a
dropping resistor in the collector bias line and a voltage
divider from collector-to-base. Using this scheme the
amplifier can be biased from a single supply voltage. The
collector-dropping resistor is sized to drop >20% VCE
depending on the desired VCE . The voltage divider from
collector-to-base, in conjunction with the dropping resistor,
will stabilize the device current over temperature.
Configuring the voltage divider such that the shunt current is
5-10 times larger than the desired base current desensitizes
the circuit to beta variation. These two feedback
mechanisms are sufficient to insure consistent performance
over temperature and device process variations. Note that
the voltage drop is clearly dependent on the nominal
collector current and can be adjusted to generate the desired
VCE from a fixed supply rail. The user should test the circuit
over the operational extremes to guarantee adequate
performance if the feedback mechanisms are reduced.
Vcc
Material: GETEK™ ML200C
Core thickness: 0.031”
Copper cladding: 1 oz. both sides
Dielectric constant: 4.1
Dielectric loss tangent: 0.0089 (@ 1 GHz)
Customers not wishing to use the exact material and
layouts shown in this application note can design their
own PCB using the critical transmission line impedances
and phase lengths shown in the BOMs and layouts.
+
VDROP
-
Ic
IB
+
VCE
-
ISHUNT
The information provided herein is believed to be reliable at press time.
RFMD assumes no responsibility for i naccuracies or omissions. RFMD assumes no responsibility for the use of this
information, and all such information shall be entirely at the user’s own risk. Prices and specifications are subject to chang
e without notice. No patent rights or licenses to any of the circuits described herein are implied or
granted to any third party . RFMD does not authorize or warrant any RFMD product for use in lif e-support devices and/or systems. Copyright 2005 RFMD All worldwide right s
reserved.
303 S. Technology Ct.
Broomfield, CO 80021
Phone: (800) SMI-MMIC
1
http://www.RFMD.com
www.BDTIC.com/RFMD
EAN-104851 Rev B
Design Application Note - AN-079
SGA-8543Z Amplifier Application Circuits
Vs = 5V
880 MHz Application Circuit (Vs=5V, Is=96mA)
20Ω, 1/4W
130Ω
10Ω
150Ω
39pF
1.1ΚΩ
are determined from
the center of a shunt component and a cut on
the center trace
Ζ=50Ω, 3.4°
Ζ=50Ω, 2.7°
Note: Electrical lengths
220pF
22nH
3.9nH
4.7nH
68pF
Ζ=50Ω, 13.1°
0.1uF
Ζ=50Ω, 3.3°
150Ω
Ζ=50Ω, 1.8°
Ζ=50Ω, 2.8°
Ζ=50Ω, 2.4°
3.9pF
Ζ=50Ω, 2.4°
68pF
5.6pF
Bill of Materials
C1
MCH182CN104K Rohm 0.1uF
C2
MCH185A221JK Rohm 220pF
C3
MCH185A680JK Rohm 68pF
C4
MCH155A5R6DK Rohm 5.6pF (0402)
C5
MCH185A390JK Rohm 39pF
C6
MCH185A3R9CK Rohm 3.9pF
C7
MCH185A680JK Rohm 68pF
L1
LL1608-FS4N7S Toko 4.7nH
L2
LL1608-FS3N9S Toko 3.9nH
L3
LL1608-FS22NJ Toko 22nH
R1
20Ω 1206, 1/4W res (5%)
R2
150Ω 0603 res (5%)
R3
130Ω 0603 res (5%)
R4
10Ω 0603 res (5%)
R5
1.1KΩ 0603 res (5%)
R6
150Ω 0402 res (5%)
Connectors 2x PSF-S01-1mm GigaLane Co.
Heat sink
EEF-102059
PCB
SOT-343 Rev B
303 S. Technology Ct.
Broomfield, CO 80021
Phone: (800) SMI-MMIC
2
http://www.RFMD.com
www.BDTIC.com/RFMD
EAN-104851 Rev B
Design Application Note - AN-079
SGA-8543Z Amplifier Application Circuits
880 MHz Application Circuit Data, VS= 5V, IS= 96mA
Noise Figure vs. Frequency
5
Gain Vs. Frequency
25
25C
4.5
4
85C
3.5
3
25C
860
870
19
17
2.5
2
850
85C
21
Gain (dB)
NF (dB)
-40C
23
880
890
900
15
850
910
860
Frequency (MHz)
Input/Output Return Loss,
Isolation vs. Frequency, T=25C
0
40
OIP3 (dBm)
-10
-15
-20
dB
880
890
900
910
OIP3 vs. Freq. (5dBm Output Tones)
38
-5
-25
36
34
32
25C
S11
-30
-40
850
860
870
880
890
900
-40C
30
S12
S22
-35
28
850
910
85C
860
Frequency (MHz)
-40C
85C
IM3
P1dB (dBm)
-50
-60
-70
-80
880
890
900
910
P1dB vs. Frequency
22
25C
-40
870
Frequency (MHz)
IM3/IM5 vs. Tone Power @880MHz
-30
IM3/IM5 (dBm)
870
Frequency (MHz)
22
25C
21
-40C
85C
21
20
20
19
IM5
-90
19
-100
-4
-2
0
2
4
6
8
10
12
18
850
Pout per tone (dBm)
303 S. Technology Ct.
Broomfield, CO 80021
860
870
880
890
900
910
Frequency (MHz)
Phone: (800) SMI-MMIC
3
http://www.RFMD.com
www.BDTIC.com/RFMD
EAN-104851 Rev B
Design Application Note - AN-079
SGA-8543Z Amplifier Application Circuits
Vs = 5V
2440 MHz Application Circuit (Vs=5V, Is=96mA)
20Ω, 1/4W
130Ω
.01uF
150Ω
5.6pF
are determined from
the center of a shunt component and a cut on
the center trace
1.2ΚΩ
100Ω
2.2pF
Ζ=50Ω, 6.7°
Ζ=50Ω, 7.9°
4.7pF
Ζ=50Ω, 7.6°
Note: Electrical lengths
Ζ=50Ω, 4°
15nH
Ζ=50Ω, 5.9°
1.5pF
Ζ=50Ω, 18.4°
Ζ=50Ω, 24.7°
1.8pF
Bill of Materials
C1
MCH182CN104K Rohm 0.1uF
C2
MCH185A2R2CK Rohm 2.2pF
C3
MCH185A4R7CK Rohm 4.7pF
C4
MCH185A1R5CK Rohm 1.5pF
C5
MCH185A5R6DK Rohm 5.6pF
C6
MCH185A1R8CK Rohm 1.8pF
L1
LL1608-FS15NJ Toko 15nH
R1
20Ω 1206, 1/4W res (5%)
R2
150Ω 0603 res (5%)
R3
130Ω 0603 res (5%)
R4
100Ω 0603 res (5%)
R5
1.2KΩ 0603 res (5%)
Connectors 2x PSF-S01-1mm GigaLane Co.
Heat sink
EEF-102059
PCB
SOT-343 Rev B
303 S. Technology Ct.
Broomfield, CO 80021
Phone: (800) SMI-MMIC
4
http://www.RFMD.com
www.BDTIC.com/RFMD
EAN-104851 Rev B
Design Application Note - AN-079
SGA-8543Z Amplifier Application Circuits
2440 MHz Application Circuit Data, VS= 5V, IS= 96mA
Noise Figure vs. Frequency
4
3.5
25C
-40C
85C
17
85C
3
15
Gain (dB)
NF (dB)
Gain Vs. Frequency
19
2.5
25C
2
13
11
1.5
1
2410
2420
2430
2440
2450
2460
9
2410
2470
2420
Frequency (MHz)
40
OIP3 (dBm)
-10
-15
-20
dB
2450
2460
2470
OIP3 vs. Freq. (5dBm Output Tones)
38
-5
-25
S11
-30
-40
2410
2420
2430
2440
2450
2460
36
34
32
25C
-40C
30
S12
S22
-35
28
2410
2470
85C
2420
Frequency (MHz)
2450
IM3
85C
P1dB (dBm)
-70
-80
IM5
21
20
20
25C
19
-90
-40C
85C
19
-100
-2
0
2
4
6
8
10
12
18
2410
Pout per tone (dBm)
303 S. Technology Ct.
Broomfield, CO 80021
2470
21
-60
-4
2460
22
-40C
-50
2440
P1dB vs. Frequency
22
25C
-40
2430
Frequency (MHz)
IM3 / IM5 vs. Tone Power @2440MHz
-30
IM3/IM5 (dBm)
2440
Frequency (MHz)
Input/Output Return Loss,
Isolation vs. Frequency, T=25C
0
2430
2420
2430
2440
2450
2460
2470
Frequency (MHz)
Phone: (800) SMI-MMIC
5
http://www.RFMD.com
www.BDTIC.com/RFMD
EAN-104851 Rev B