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 P1dB 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
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 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
RF
INPUT
1
24GROUNDGROUND
RF OUTPUT
AND V
d
3
Pin Connections
RF OUTPUT
AND V
d
RF INPUT
13
2
4 GROUND
GROUND
865
2
Absolute Maximum Ratings
Absolute
Symbol Parameter Units Maximum[1]
VdDevice Voltage, RF output V 9
to ground
VgDevice Voltage, RF input V +0.5
to ground -1.0
Pin CW RF Input Power dBm +13
Tch Channel Temperature °C 150
TSTG Storage Temperature °C -65 to 150
MGA-86576 Electrical Specifications, TC = 25°C, Zo = 50 Ω, Vd = 5 V
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
NF50 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
NFoOptimum 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
P1dB 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
IP3Third 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
IdDevice Current mA 9 16 22
Thermal Resistance[2]:
θch-c = 110°C/W
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).
3
MGA-86576 Typical Scattering Parameters [3], TC = 25°C, Zo = 50 Ω, Vd = 5 V
S11 S21 S12 S22
Freq.
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
MGA-86576 Typical Performance, TC = 25°C, Zo = 50 Ω, Vd = 5 V
Figure 3. Matched Noise Figure vs.
Frequency.
Figure 1. Power Gain vs. Frequency at
Three Temperatures.
GAIN (dB)
1
30.0
5.0
FREQUENCY (GHz)
4710
25.0
20.0
15.0
10.0
23 56 89
-40°C
+25°C
+50°C
NF (dB)
1
3.5
1
FREQUENCY (GHz)
4710
3
2.5
2
1.5
23 56 89
+50°C
-40°C
+25°C
NF (dB)
1
3.5
1
FREQUENCY (GHz)
4710
3
2.5
2
1.5
23 56 89
Figure 2. 50 Ω Noise Figure vs.
Frequency at Three Temperatures.
Figure 4. P1dB vs. Frequency at Three
Temperatures. Figure 5. Input and Output VSWR vs.
Frequency. Figure 6. Gain, NF50, and P1dB vs.
Temperature at 4 GHz.
P
1dB
(dBm)
1
10.0
0
FREQUENCY (GHz)
4710
8.0
6.0
4.0
2.0
23 56 89
-40°C
+25°C
+50°C
VSWR
1
4.0
1.5
FREQUENCY (GHz)
4710
3.5
3.0
2.5
2.0
23 56 89
OUTPUT
1.0
INPUT
GAIN AND NF (dB)
-40
25
0
TEMPERATURE °C
-20 0 50
20
15
10
5
-30 -10 25
POWER GAIN
NOISE FIGURE
P
1dB
(dBm)
P
1dB
0
+5
+10
4
MGA-86576 Typical Noise Parameters[3],
TC = 25°C, Zo = 50 Ω, Vd = 5 V
Γopt
Frequency NFo
GHz dB Mag. Ang. RN/50 Ω
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.
Figure 7. Layout for MGA-86576
Demonstration Amplifier. PCB
dimensions are 1.18 inches wide by
1.30 inches high.
recommend using the MGA-86576
MMIC on boards thicker than
0.040 inch.
The effects of inductance asso-
ciated 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
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 para-
sitic 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
100-1000 pF C1 V
dd
HIGH Z
10-100 Ω
27 pF
50 Ω50 Ω50 Ω50 Ω
4
2
31 27 pF
L1
R1
Figure 8. Demonstration Amplifier Schematic.
5
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 micro-
stripline 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
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.
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.
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 appro-
priate for operation at 1.5 GHz.
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
Printed Circuit Board
Materials
Most commercial applications
dictate the need to use inexpen-
sive 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
MGA-86576 Part Number Ordering Information
Part Number No. of Devices Container
MGA-86576-STR 10 Strip
MGA-86576-TR1 1000 7-inch Reel
For more information call your nearest HP sales office.
dB OR dE
-40
25
0
TEMPERATURE °C
-20 0 50
20
15
10
5
-30 -10 25
POWER GAIN
NOISE FIGURE
P
1dB
85 125
Figure 10. Gain, NF50, and P1dB vs.
Temperature at 4 GHz with 7 Volt Bias
Supply.
Package Dimensions
76 Package
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).
loss PTFE based dielectric
material will preserve the
inherent low noise of the
MGA-86576.
For technical assistance or the location of
your nearest Hewlett-Packard sales office,
distributor or representative call:
Americas/Canada: 1-800-235-0312 or
408-654-8675
Far East/Australasia: Call your local HP
sales office.
Japan: (81 3) 3335-8152
Europe: Call your local HP sales office.
Data subject to change.
Copyright © 1997 Hewlett-Packard Co.
Obsoletes 5962-6909E
Printed in U.S.A. 5965-9687E (9/97)
