MGA-86576
1.5 – 8 GHz Low Noise
GaAs MMIC Amplifier
Data Sheet
Description
Features
Avago’s MGA-86576 is an economical, easy-to-use GaAs
MMIC amplifier that offers low noise and excellent gain
for applications from 1.5 to 8 GHz.
• 1.6 dB Noise Figure at 4 GHz
The MGA-86576 may be used without impedance matching
as a high performance 2 dB NF gain block. Alternatively,
with the addition of a simple series inductor at the input, the
device noise figure can be reduced to 1.6 dB at 4 GHz.
• Single +5 V Bias Supply
The circuit uses state-of-the-art PHEMT technology with
self-biasing current sources, a source-follower interstage,
resistive feedback, and on chip impedance matching
networks.
A patented, on-chip active bias circuit allows operation
from a single +5 V power supply. Current consumption
is only 16 mA.
These devices are 100% RF tested to assure consistent
performance.
Surface Mount Ceramic Package
• 23 dB Gain at 4 GHz
• +6 dBm P1dB at 4 GHz
Applications
• LNA or Gain Stage for 2.4 GHz and 5.7 GHz ISM Bands
• Front End Amplifier for GPS Receivers
• LNA or Gain Stage for PCN and MMDS Applications
• C-Band Satellite Receivers
• Broadband Amplifier for Instrumentation
Schematic Diagram
RF OUTPUT
AND Vd
RF
INPUT
3
1
GROUND
2
GROUND
4
Pin Connections
MGA-86576 Pkg
4
RF OUTPUT
AND Vd
865
RF INPUT
MGA-86576 Schematic
Attention: Observe precautions for
handling electrostatic sensitive devices.
GROUND
1
3
2
GROUND
MGA-86576 Pin Connection
ESD Machine Model (Class A)
ESD Human Body Model (Class 0)
Refer to Avago Application Note A004R:
Electrostatic Discharge Damage and Control.
Absolute Maximum Ratings
Symbol Parameter
Units
Thermal Resistance[2]:
θch-c = 110°C/W
Absolute
Maximum[1]
Vd
Device Voltage, RF output
to ground
V
9
Vg
Device Voltage, RF input
to ground
V
+0.5
-1.0
Pin
CW RF Input Power
dBm
+13
Tch
Channel Temperature
°C
150
TSTG
Storage Temperature
°C
-65 to 150
Notes:
1. Operation of this device above any one of
these limits may cause permanent damage.
2. Tc = 25°C (Tc is defined to be the temperature at the package pins where contact is
made to the circuit board).
MGA-86576 Electrical Specifications, TC = 25°C, Zo = 50 Ω, Vd = 5 V
Symbol Parameters and Test Conditions
Units
Min.
Typ.
Gp
Power Gain (|S21|2)
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
dB
20
21.2
23.7
23.1
19.3
15.4
NF50
50 Ω Noise Figure
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
dB
2.2
1.9
2.0
2.3
2.5
NFo
Optimum Noise Figure
(Input tuned for lowest noise
figure)
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
dB
1.6
1.5
1.6
1.8
2.1
P1dB
Output Power at 1 dB Gain
Compression
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
dBm
6.4
7.0
6.3
4.3
3.8
IP3
Third Order Intercept Point
f = 4.0 GHz
dBm
16.0
VSWR
Input VSWR
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
3.6:1
3.3:1
2.2:1
1.4:1
1.2:1
Output VSWR
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
2.5:1
2.1:1
1.7:1
1.4:1
1.3:1
Id
Device Current
mA
9
16
Max.
2.3
3.6:1
22
MGA-86576 Typical Performance, TC = 25°C, Zo = 50 Ω, Vd = 5 V
30.0
-40°C
25.0
3.5
3.5
3
3
+50°C
2.5
15.0
10.0
5.0
2.5
+50°C
2
2
3
4
5
6
7
8
9
1
10
-40°C
1
2
1.5
3
4
FREQUENCY (GHz)
5
6
7
8
9
1
10
1
2
3
4
Figure 2. 50 Ω Noise Figure vs. Frequency at Three
Temperatures.
MGA-86576 fig 1
3.5
7
8
9
10
MGA-86576 fig 3
25
-40°C
8.0
6
Figure 3. Matched Noise Figure vs. Frequency.
MGA-86576 fig 2
4.0
5
FREQUENCY (GHz)
FREQUENCY (GHz)
Figure 1. Power Gain vs. Frequency at Three Temperatures.
10.0
2
+25°C
1.5
1
NF (dB)
20.0
NF (dB)
GAIN (dB)
+25°C
POWER GAIN
INPUT
20
+50°C
4.0
2.5
2.0
2.0
0
OUTPUT
1.5
1
2
3
4
5
6
7
8
9
1.0
10
15
10
5
+5
NOISE FIGURE
1
2
3
FREQUENCY (GHz)
4
5
6
7
8
9
10
0
-40
Figure 5. Input and Output VSWR vs. Frequency.
MGA-86576 fig 4
-30
-20
-10
0
25
0
50
TEMPERATURE °C
FREQUENCY (GHz)
Figure 4. P1dB vs. Frequency at Three Temperatures.
+10
P1dB
Figure 6. Gain, NF50, and P1dB vs. Temperature at 4
GHz.
MGA-86576 fig 6
MGA-86576 fig 5
MGA-86576 Typical Scattering Parameters [3], TC = 25°C, Zo = 50 Ω, Vd = 5 V
Freq. S11
GHz
Mag
Ang
dB
S21
Mag
Ang
dB
S12 S22
Mag
Ang
Mag
Ang
5.99
9.72
12.15
13.84
14.98
15.56
15.28
14.49
13.18
11.82
10.54
9.14
8.08
7.48
6.64
5.99
5.45
5.03
4.66
4.33
0.005
0.003
0.003
0.004
0.007
0.010
0.014
0.018
0.022
0.026
0.030
0.033
0.037
0.042
0.047
0.051
0.056
0.062
0.068
0.074
-35
-47
-57
-68
-79
-92
-105
-118
-130
-139
-151
-151
-116
-158
-153
-151
-146
-140
-143
-154
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
0.57
0.55
0.54
0.52
0.48
0.43
0.37
0.30
0.24
0.19
0.14
0.12
0.10
0.08
0.08
0.07
0.06
0.04
0.02
0.01
-21
-30
-44
-59
-77
-96
-116
-137
-159
178
151
129
111
91
75
64
48
31
18
93
15.5
19.8
21.7
22.8
23.5
23.8
23.7
23.2
22.4
21.5
20.5
19.2
18.1
17.5
16.4
15.5
14.7
14.0
13.4
12.7
46
17
-7
-31
-54
-77
-100
-122
-142
-160
-177
166
156
142
129
118
107
96
86
76
-46.5
-51.3
-51.2
-47.0
-43.0
-39.7
-37.0
-35.0
-33.2
-31.9
-30.6
-29.6
-28.7
-27.4
-26.6
-25.8
-25.0
-24.2
-23.4
-22.6
-15
11
58
85
96
100
99
95
92
89
85
81
82
76
72
69
65
62
58
53
0.62
0.49
0.43
0.39
0.36
0.33
0.29
0.25
0.21
0.19
0.14
0.17
0.14
0.08
0.11
0.09
0.09
0.09
0.11
0.11
P1dB (dBm)
GAIN AND NF (dB)
3.0
6.0
VSWR
P1dB (dBm)
+25°C
MGA-86576 Typical Noise Parameters[3],
TC = 25°C, Zo = 50 Ω, Vd = 5 V
Frequency
NFo Γopt
GHz
dB
Mag.
Ang.
RN/50 Ω
27
31
40
54
77
107
0.43
0.40
0.36
0.32
0.28
0.25
1.0
1.5
2.5
4.0
6.0
8.0
[3]Reference
2.1
1.6
1.5
1.6
1.8
2.1
0.56
0.54
0.47
0.38
0.28
0.22
plane taken at point where leads meet body of package.
MGA-86576 Applications Information
Introduction
The MGA-86576 is a high gain, broad band, low noise
amplifier. The use of plated through holes or an equivalent minimal inductance grounding technique placed
precisely under each ground lead at the device is highly
recom-mended. A minimum of two plated through holes
under each ground lead is preferred with four being highly
suggested. A long ground path to pins 2 and 4 will add
additional inductance which can cause gain peaking in the
2 to 4 GHz frequency range. This can also be accompanied
by a decrease in stability. A suggested layout is shown in
Figure 7. The circuit is designed for use on 0.031 inch thick
FR-4/G-10 epoxy glass dielectric material.
Printed circuit board thickness is also a major consideration. Thicker printed circuit boards dictate longer
plated through holes which provide greater undesired
inductance. The parasitic inductance associated with a
pair of plated through holes passing through 0.031 inch
thick printed circuit board is approximately 0.1 nH, while
the inductance of a pair of plated through holes passing
through 0.062 inch thick board is about 0.2 nH. Avago does
not recommend using the MGA-86576 MMIC on boards
thicker than 0.040 inch.
The effects of inductance associated with the board
material are easily analyzed and very predict-able. As a
minimum, the circuit simulation should consist of the data
sheet S-Parameters and an additional circuit file describing
the plated through holes and any additional inductance
associated with lead length between the device and the
start of the plated through hole. To obtain a complete
analysis of the entire amplifier circuit, the effects of the
input and output microstriplines and bias decoupling
circuits should be incorporated into the circuit file.
Device Connections Vd and RF Output (Pin 3)
RF and DC connections are shown in Figure 8. DC power
is provided to the MMIC through the same pin used to
obtain RF output. A 50 Ω microstripline is used to connect
the device to the following stage or output connector.
A bias decoupling network is used to feed in Vdd while
simultaneously providing a DC block to the RF signal. The
bias decoupling network shown in Figure 8, consisting of
resistor R1, a short length of high impedance microstripline, and bypass capacitor C1, provides the best overall
performance in the 2 to 8 GHz frequency range.
C1
100-1000 pF
Vdd
HIGH Z
R1
27 pF
50 Ω
Figure 7. Layout for MGA-86576 Demonstration Amplifier.
PCB dimensions are 1.18 inches wide by 1.30 inches high.
L1
50 Ω
1
4
10-100 Ω
27 pF
3
2
MGA-86576 fig 8
Figure 8. Demonstration Amplifier Schematic.
50 Ω
50 Ω
The use of lumped inductors is not desired since they
tend to radiate and cause undesired feedback. Moving the
bypass capacitor, C1, down the microstripline towards the
Vdd terminal, as shown in Figure 9, will improve the gain
below 2 GHz by trading off some high end gain. A minimum value of 10 Ω for R1 is recommended to de-Q the
bias decoupling network, although 100 Ω will provide the
highest circuit gain over the entire 1.5 to 8 GHz frequency
range. Vdd will have to be increased accordingly for higher
values of R1. For operation in the 2 to 6 GHz frequency
range, a 10 pF capacitor may be used for DC blocking on
the output microstripline. A larger value such as 27 pF is
more appropriate for operation at 1.5 GHz.
Table 1 provides the approximate inductor length for
minimum noise figure at a given frequency for the circuit
board shown in Figure 7.
Table 1. L1 Length vs. Frequency for Optimum Noise Figure.
Frequency
GHz
1.5
1.8
2.1
2.4
2.5
3.0
3.7
4.0
Length
Inches
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.05
7 Volt Bias for Operation at Higher Temperatures
Ground (Pins 2 and 4)
Ground pins should attach directly to the backside ground
plane by the shortest distance possible using the design
hints suggested in the earlier section. Liberal use of plated
through vias is recommended.
RF Input (Pin 1)
A 50 Ω microstripline can be used to feed RF to the device. A blocking capacitor in the 10 pF range will provide
a suitable DC block in the 2 to 6 GHz frequency range.
Although there is no voltage present at pin 1, it is highly
suggested that a DC blocking capacitor be used to prevent
accidental application of a voltage from a previous amplifier stage. With no further input matching, the MGA-86576
is capable of noise figures as low as 2 dB in the 2 to 6 GHz
frequency range. Since Γo is not 50 Ω, it is possible to design and implement a very simple matching network in
order to improve noise figure and input return loss over a
narrow frequency range. The circuit board layout shown
in Figure 7 provides an option for tuning for a low noise
match anywhere in the 1.5 to 4 GHz frequency range. For
optimum noise figure performance in the 4 GHz frequency
range, L1 can be a 0.007 inch diameter wire 0.080 inches
in length as shown in Figure 9. Alternatively, L1 can be
replaced by a 0.020 inch wide microstripline whose length
can be adjusted for minimum noise figure in the 1.5 to 4
GHz frequency range.
25
POWER GAIN
20
dB OR dE
Figure 9. Complete MGA-86576 Demonstration Amplifier.
The MGA-86576 was designed primarily for 5 volt operation over the -25 to +50°C temperature range. For
applications requiring use to +85°C, a 7 volt bias supply
is recommended to minimize changes in gain and noise
figure at elevated temperature. Figure 10 shows typical
gain, noise figure, and output power performance over
temperature at 4 GHz with 7 volts applied. With a 7 volt
bias supply, output power is increased approximately 1.5
dB. Other parameters are relatively unchanged from 5 volt
data. S‑parameter and noise parameter data for 7 volts are
available upon request from Avago.
15
10
P1dB
5
NOISE FIGURE
0
-40
-30
-20
-10
0
25
50
85
TEMPERATURE °C
Figure 10. Gain, NF50, and P1dB vs. Temperature at 4
GHz with 7 Volt Bias Supply.
MGA-86576 fig 10
125
Printed Circuit Board Materials
Most commercial applications dictate the need to use
inexpensive epoxy glass materials such as FR-4 or G-10.
Unfortunately the losses of this type of material can become
excessive above 2 GHz. As an example, a 0.5 inch long
50 Ω microstripline etched on FR‑4 along with a blocking
capacitor has a measured loss of 0.35 dB at 4 GHz. The 0.35
dB loss adds directly to the noise figure of the MGA-86576.
The use of a low loss PTFE based dielectric material will
preserve the inherent low noise of the MGA‑86576.
Package Dimensions
76 Package
1.02
(0.040)
.51
(0.20)
Part Number Ordering Information
Part Number
MGA-86576-TR1
MGA-86576-STRG
No. of
Devices
1000
100
1.78
(0.070)
Container
7" Reel
Strips
1.22
(0.048)
5.28
(0.208)
.53
(0.021)
0.10
(0.004)
TYPICAL DIMENSIONS ARE IN MILLIMETERS (INCHES).
MGA-86576 Pkg Dimensions
For product information and a complete list of distributors, please go to our web site:
www.avagotech.com
vago, Avago Technologies, and the A logo are trademarks of Avago Technologies Limited in the United States and other countries.
Data subject to change. Copyright © 2005-2008 Avago Technologies Limited. All rights reserved. Obsoletes 5989-4658EN
AV02-0608EN - April 29, 2008
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