MGA-86576
1.5 – 8 GHz Low Noise
GaAs MMIC Amplifier
Data Sheet
Description
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.
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.
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.
Features
•
1.6 dB Noise Figure at 4 GHz
•
23 dB Gain at 4 GHz
•
+6 dBm P
1dB
at 4 GHz
•
Single +5 V Bias Supply
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
INPUT
1
RF OUTPUT
AND V
d
3
Surface Mount Ceramic Package
GROUND
2
GROUND
4
Pin Connections
MGA-86576 Pkg
4
GROUND
Attention: Observe precautions for
handling electrostatic sensitive devices.
RF OUTPUT
AND V
d
3
MGA-86576 Schematic
1
865
RF INPUT
ESD Machine Model (Class A)
ESD Human Body Model (Class 0)
Refer to Avago Application Note A004R:
Electrostatic Discharge Damage and Control.
2
GROUND
MGA-86576 Pin Connection
Absolute Maximum Ratings
Symbol
V
d
V
g
P
in
T
ch
T
STG
Parameter
Device Voltage, RF output
to ground
Device Voltage, RF input
to ground
CW RF Input Power
Channel Temperature
Storage Temperature
Units
V
V
dBm
°C
°C
Absolute
Maximum
[1]
9
+0.5
-1.0
+13
150
-65 to 150
Thermal Resistance
[2]
:
θ
ch-c
= 110°C/W
Notes:
1. Operation of this device above any one of
these limits may cause permanent dam-
age.
2. T
c
= 25°C (T
c
is defined to be the tempera-
ture at the package pins where contact is
made to the circuit board).
MGA-86576 Electrical Specifications,
T
C
= 25°C, Z
o
= 50 Ω, V
d
= 5 V
Symbol
Gp
NF
50
NF
o
P
1dB
IP
3
VSWR
I
d
Parameters and Test Conditions
Power Gain (|S
21
|
2
)
50 Ω Noise Figure
Optimum Noise Figure
(Input tuned for lowest noise
figure)
Output Power at 1 dB Gain
Compression
Third Order Intercept Point
Input VSWR
Output VSWR
Device Current
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
f = 4.0 GHz
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
f = 1.5 GHz
f = 2.5 GHz
f = 4.0 GHz
f = 6.0 GHz
f = 8.0 GHz
Units
dB
dB
dB
dBm
dBm
mA
Min.
20
9
Typ.
21.2
23.7
23.1
19.3
15.4
2.2
1.9
2.0
2.3
2.5
1.6
1.5
1.6
1.8
2.1
6.4
7.0
6.3
4.3
3.8
16.0
3.6:1
3.3:1
2.2:1
1.4:1
1.2:1
2.5:1
2.1:1
1.7:1
1.4:1
1.3:1
16
Max.
2.3
3.6:1
22
2
MGA-86576 Typical Performance,
T
C
= 25°C, Z
o
= 50 Ω, V
d
= 5 V
30.0
-40°C
+25°C
3.5
3.5
25.0
3
3
GAIN (dB)
20.0
+50°C
2.5
2.5
NF (dB)
+50°C
2
+25°C
-40°C
15.0
NF (dB)
2
10.0
1.5
1.5
5.0
1
2
3
4
5
6
7
8
9
10
1
1
2
3
4
5
6
7
8
9
10
1
1
2
3
4
5
6
7
8
9
10
FREQUENCY (GHz)
FREQUENCY (GHz)
FREQUENCY (GHz)
Figure 1. Power Gain vs. Frequency at Three Tempera-
tures.
10.0
-40°C
8.0
+25°C
Figure 2. 50 Ω Noise Figure vs. Frequency at Three
Temperatures.
4.0
3.5
3.0
INPUT
MGA-86576 fig 2
Figure 3. Matched Noise Figure vs. Frequency.
25
MGA-86576 fig 3
MGA-86576 fig 1
POWER GAIN
20
GAIN AND NF (dB)
P
1dB
(dBm)
2.5
2.0
4.0
10
P
1dB
5
NOISE FIGURE
+10
2.0
1.5
1.0
OUTPUT
+5
0
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
0
-40
-30
-20
-10
0
25
0
50
FREQUENCY (GHz)
FREQUENCY (GHz)
TEMPERATURE °C
Figure 4. P
1dB
vs. Frequency at Three Temperatures.
MGA-86576 fig 4
Figure 5. Input and Output VSWR vs. Frequency.
MGA-86576 fig 5
Figure 6. Gain, NF
50
, and P
1dB
vs. Temperature at 4
GHz.
MGA-86576 fig 6
MGA-86576 Typical Scattering Parameters
[3]
,
T
C
= 25°C, Z
o
= 50 Ω, V
d
= 5 V
Freq.
GHz
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
S
11
Mag
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
Ang
-21
-30
-44
-59
-77
-96
-116
-137
-159
178
151
129
111
91
75
64
48
31
18
93
dB
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
S
21
Mag
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
Ang
46
17
-7
-31
-54
-77
-100
-122
-142
-160
-177
166
156
142
129
118
107
96
86
76
dB
-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
S
12
Mag
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
S
22
Ang
-15
11
58
85
96
100
99
95
92
89
85
81
82
76
72
69
65
62
58
53
Mag
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
Ang
-35
-47
-57
-68
-79
-92
-105
-118
-130
-139
-151
-151
-116
-158
-153
-151
-146
-140
-143
-154
3
P
1dB
(dBm)
6.0
+50°C
15
VSWR
MGA-86576 Typical Noise Parameters
[3]
,
T
C
= 25°C, Z
o
= 50 Ω, V
d
= 5 V
Frequency
NF
o
GHz
1.0
1.5
2.5
4.0
6.0
8.0
Γopt
Mag.
0.56
0.54
0.47
0.38
0.28
0.22
dB
2.1
1.6
1.5
1.6
1.8
2.1
Ang.
27
31
40
54
77
107
R
N
/50 Ω
0.43
0.40
0.36
0.32
0.28
0.25
[3]
Reference 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 equiva-
lent 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 consid-
eration. 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 V
d
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 V
dd
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 microstrip-
line, and bypass capacitor C1, provides the best overall
performance in the 2 to 8 GHz frequency range.
C1
100-1000 pF
V
dd
HIGH Z
R1
27 pF
50
Ω
50
Ω
L1
1
4
3
10-100
Ω
27 pF
50
Ω
50
Ω
2
Figure 7. Layout for MGA-86576 Demonstration Amplifier.
PCB dimensions are 1.18 inches wide by 1.30 inches high.
Figure 8. Demonstration Amplifier Schematic.
MGA-86576 fig 8
4
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
V
dd
terminal, as shown in Figure 9, will improve the gain
below 2 GHz by trading off some high end gain. A mini-
mum 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. V
dd
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
The MGA-86576 was designed primarily for 5 volt op-
eration 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.
25
POWER GAIN
20
Figure 9. Complete MGA-86576 Demonstration Amplifier.
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 de-
vice. 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 ampli-
fier 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 Γ
o
is not 50 Ω, it is possible to de-
sign 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.
dB OR dE
15
10
P
1dB
5
NOISE FIGURE
0
-40
-30
-20
-10
0
25
50
85
125
TEMPERATURE °C
Figure 10. Gain, NF
50
, and P
1dB
vs. Temperature at 4
GHz with 7 Volt Bias Supply.
MGA-86576 fig 10
5
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