1.5 – 8 GHz Low Noise GaAs
MMIC Amplifier
Technical Data
MGA-86576
Features
• 1.6 dB Noise Figure at 4 GHz
• 23 dB Gain at 4 GHz
• +6 dBm P
at 4 GHz
1dB
• 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
Surface Mount Ceramic Package
Pin Connections
4 GROUND
GROUND
RF OUTPUT
AND V
d
RF INPUT
13
865
2
RF OUTPUT
AND V
d
3
Description
Hewlett-Packard’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 selfbiasing current sources, a sourcefollower 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.
5965-9687E
These devices are 100% RF tested
to assure consistent performance.
24GROUNDGROUND
6-228
Absolute Maximum Ratings
Absolute
Symbol Parameter Units Maximum
V
d
V
g
P
in
T
ch
T
STG
Device Voltage, RF output V 9
to ground
Device Voltage, RF input V +0.5
to ground -1.0
CW RF Input Power dBm +13
Channel Temperature °C 150
Storage Temperature °C -65 to 150
[1]
Thermal Resistance
θ
= 110°C/W
ch-c
Notes:
1. Operation of this device above any one
of these limits may cause permanent
damage.
2. T
= 25°C (T
c
temperature at the package pins where
contact is made to the circuit board).
is defined to be the
c
[2]
:
MGA-86576 Electrical Specifications, T
= 25° C, Zo = 50 Ω, V
C
= 5 V
d
Symbol Parameters and Test Conditions Units Min. Typ. Max.
Gp Power Gain (|S21|2) f = 1.5 GHz dB 21.2
f = 2.5 GHz 23.7
f = 4.0 GHz 20 23.1
f = 6.0 GHz 19.3
f = 8.0 GHz 15.4
NF
50
50 Ω Noise Figure f = 1.5 GHz dB 2.2
f = 2.5 GHz 1.9
f = 4.0 GHz 2.0 2.3
f = 6.0 GHz 2.3
f = 8.0 GHz 2.5
NF
o
Optimum Noise Figure f = 1.5 GHz dB 1.6
(Input tuned for lowest noise f = 2.5 GHz 1.5
figure) f = 4.0 GHz 1.6
f = 6.0 GHz 1.8
f = 8.0 GHz 2.1
P
1dB
Output Power at 1 dB Gain f = 1.5 GHz dBm 6.4
Compression f = 2.5 GHz 7.0
f = 4.0 GHz 6.3
f = 6.0 GHz 4.3
f = 8.0 GHz 3.8
IP
3
Third Order Intercept Point f = 4.0 GHz dBm 16.0
VSWR Input VSWR f = 1.5 GHz 3.6:1
f = 2.5 GHz 3.3:1
f = 4.0 GHz 2.2:1 3.6:1
f = 6.0 GHz 1.4:1
f = 8.0 GHz 1.2:1
Output VSWR f = 1.5 GHz 2.5:1
f = 2.5 GHz 2.1:1
f = 4.0 GHz 1.7:1
f = 6.0 GHz 1.4:1
f = 8.0 GHz 1.3:1
I
d
Device Current mA 9 16 22
6-229
MGA-86576 Typical Performance, T
30.0
3.5
= 25°C, Zo = 50 Ω, V
C
= 5 V
d
3.5
25.0
20.0
15.0
GAIN (dB)
10.0
-40°C
+25°C
+50°C
5.0
1
4710
23 56 89
FREQUENCY (GHz)
Figure 1. Power Gain vs. Frequency at
Three Temperatures.
10.0
-40°C
8.0
+25°C
6.0
+50°C
(dBm)
1dB
4.0
P
2.0
0
1
23 56 89
4710
FREQUENCY (GHz)
Figure 4. P
Temperatures.
vs. Frequency at Three
1dB
3
2.5
+50°C
NF (dB)
2
+25°C
-40°C
1.5
1
1
4710
23 56 89
FREQUENCY (GHz)
Figure 2. 50 Ω Noise Figure vs.
Frequency at Three Temperatures.
4.0
3.5
INPUT
3.0
2.5
VSWR
2.0
OUTPUT
1.5
1.0
1
23 56 89
4710
FREQUENCY (GHz)
Figure 5. Input and Output VSWR vs.
Frequency.
3
2.5
NF (dB)
2
1.5
1
1
4710
23 56 89
FREQUENCY (GHz)
Figure 3. Matched Noise Figure vs.
Frequency.
25
20
15
10
GAIN AND NF (dB)
5
0
-40
Figure 6. Gain, NF50, and P
Temperature at 4 GHz.
POWER GAIN
P
1dB
NOISE FIGURE
-30
-10
-20 0 50
TEMPERATURE °C
1dB
25
vs.
+10
+5
0
(dBm)
1dB
P
MGA-86576 Typical Scattering Parameters
Freq.
S
11
S
21
[3]
, T
= 25° C, Zo = 50 Ω, V
C
= 5 V
d
S
12
S
GHz Mag Ang dB Mag Ang dB Mag Ang Mag Ang
0.5 0.57 -21 15.5 5.99 46 -46.5 0.005 -15 0.62 -35
1.0 0.55 -30 19.8 9.72 17 -51.3 0.003 11 0.49 -47
1.5 0.54 -44 21.7 12.15 -7 -51.2 0.003 58 0.43 -57
2.0 0.52 -59 22.8 13.84 -31 -47.0 0.004 85 0.39 -68
2.5 0.48 -77 23.5 14.98 -54 -43.0 0.007 96 0.36 -79
3.0 0.43 -96 23.8 15.56 -77 -39.7 0.010 100 0.33 -92
3.5 0.37 -116 23.7 15.28 -100 -37.0 0.014 99 0.29 -105
4.0 0.30 -137 23.2 14.49 -122 -35.0 0.018 95 0.25 -118
4.5 0.24 -159 22.4 13.18 -142 -33.2 0.022 92 0.21 -130
5.0 0.19 178 21.5 11.82 -160 -31.9 0.026 89 0.19 -139
5.5 0.14 151 20.5 10.54 -177 -30.6 0.030 85 0.14 -151
6.0 0.12 129 19.2 9.14 166 -29.6 0.033 81 0.17 -151
6.5 0.10 111 18.1 8.08 156 -28.7 0.037 82 0.14 -116
7.0 0.08 91 17.5 7.48 142 -27.4 0.042 76 0.08 -158
7.5 0.08 75 16.4 6.64 129 -26.6 0.047 72 0.11 -153
8.0 0.07 64 15.5 5.99 118 -25.8 0.051 69 0.09 -151
8.5 0.06 48 14.7 5.45 107 -25.0 0.056 65 0.09 -146
9.0 0.04 31 14.0 5.03 96 -24.2 0.062 62 0.09 -140
9.5 0.02 18 13.4 4.66 86 -23.4 0.068 58 0.11 -143
10.0 0.01 93 12.7 4.33 76 -22.6 0.074 53 0.11 -154
22
6-230
MGA-86576 Typical Noise Parameters
T
= 25° C, Zo = 50 Ω, V
C
Frequency NF
GHz dB Mag. Ang. R
1.0 2.1 0.56 27 0.43
1.5 1.6 0.54 31 0.40
2.5 1.5 0.47 40 0.36
4.0 1.6 0.38 54 0.32
6.0 1.8 0.28 77 0.28
8.0 2.1 0.22 107 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 equivalent minimal inductance
grounding technique placed
precisely under each ground lead
at the device is highly recommended. 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
= 5 V
d
o
Γopt
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. Hewlett-Packard does not
[3]
,
recommend using the MGA-86576
MMIC on boards thicker than
0.040 inch.
/50 Ω
N
The effects of inductance associated with the board material are
easily analyzed and very predictable. 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 V
dd
Figure 7. Layout for MGA-86576
Demonstration Amplifier. PCB
dimensions are 1.18 inches wide by
1.30 inches high.
V
C1
100-1000 pF
27 pF
50 Ω 50 Ω 50 Ω 50 Ω
Figure 8. Demonstration Amplifier Schematic.
L1
dd
HIGH Z
10-100 Ω
R1
4
31
2
27 pF
6-231
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.
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
Figure 9. Complete MGA-86576
Demonstration Amplifier.
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.
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.
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 Length
GHz Inches
1.5 0.70
1.8 0.60
2.1 0.50
2.4 0.40
2.5 0.30
3.0 0.20
3.7 0.10
4.0 0.05
7 Volt Bias for Operation at Higher Temperatures
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 Hewlett-Packard.
6-232
25
1.02
(0.040)
.51
(0.20)
1.78
(0.070)
1.22
(0.048)
.53
(0.021)
5.28
(0.208)
0.10
(0.004)
TYPICAL DIMENSIONS ARE IN MILLIMETERS (INCHES).
POWER GAIN
20
Printed Circuit Board Materials
Most commercial applications
15
dictate the need to use inexpensive epoxy glass materials such as
10
dB OR dE
5
0
-30
-40
Figure 10. Gain, NF50, and P
Temperature at 4 GHz with 7 Volt Bias
P
1dB
NOISE FIGURE
-10
-20 0 50
TEMPERATURE °C
25
1dB
85 125
vs.
Supply.
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
MGA-86576 Part Number Ordering Information
Part Number No. of Devices Container
MGA-86576-STR 10 Strip
MGA-86576-TR1 1000 7-inch Reel
loss PTFE based dielectric
material will preserve the
inherent low noise of the
MGA-86576.
Package Dimensions
76 Package
For more information call your nearest HP sales office.
6-233
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d
A
6
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E
D
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