LNA implementation

Report
LNA implementation
Federico Perini
AA-low Technical Progress Meeting
Medicina, 22-23 September 2012
50Ohm AAlo LNA
Fig 1. LNA schematic.
Table 1. Bill of materials.
C1
C2
C3
C4
C5
C6
L1
L2
Q1
Q2
C1
C2
C3
C4
C5
C6
L1
L2
Q1
Q2
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 100nF, 0603, GRM188R71H104KA93
AVX, 4.7uF, Case B, TAJB475K010RNJ
AVX, 1uF, Case B, TAJB105K035RNJ
Coilcraft, 1.2uF, 1008LS-122XJLB
Minicircuits, RF choke, ADCH-80A
RFMD, MMIC Amplifier, SPF-5122Z
National Semiconductors, LDO regulator, LP2950
3V, 60mA (included LDO)
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 100nF, 0603, GRM188R71H104KA93
AVX, 4.7uF, Case B, TAJB475K010RNJ
AVX, 1uF, Case B, TAJB105K035RNJ
Coilcraft, 1.2uF, 1008LS-122XJLB
Minicircuits, RF choke, ADCH-80A
RFMD, MMIC Amplifier, SPF-5122Z
National Semiconductors, LDO regulator, LP2950
Q1
RFin
C1
L1
C3
C4
RFout
DCin
C2
Q2
C5
L2
C6
Fig 2. Top view layout (Q2 is mounted on the bottom layer).
LNA for Vivaldi (August 2011)
2 samples shipped to
Perth for (active)
antenna pattern
measurement on mast
1 LNA for measurement and test
(presented in Perth September 2011)
LNA Datasheet (March 2012)
General description
The LNA is based on the RF Micro Devices SPF-5122Z low noise MMIC amplifier. The biasing network (input
and output DC block and the output choke) has been designed in order to optimise the LNA performance in
the desired frequency band 50-450MHz. DC power is provided through the output RF connector. Both +3V
and +5V DC supplies are allowed by the MMIC but, in order to reduce both power consumption and noise
figure, the former (3V, 58mA) has been chosen. To keep the correct MMIC bias point, which has to be
independent from the DC losses of the output coaxial cable, a low dropout (LDO) voltage regulator (LP2950)
has been included in the LNA. If the RFI scenario would request more dynamic range, the +5V bias point has
to be chosen. In order to do that, the only operation requested is to replace the LDO regulator. The LNA
doesn’t include any gain equalization network since it will be included further in the receiver chain.
Schematic, bill of materials and layout.
The LNA is based on the following technological choices:
1.
Printed circuit board (PCB) on FR4 (h=1.6mm, t=17.5um, r=4.7).
2.
PCB production through LPKF milling machine.
3.
Via holes metallisation with ProConduct paste.
4.
SMA 50Ohm input and output connectors, LNA version for measurements in the lab.
5.
TNC 50Ohm input and output connectors, LNA version to be mounted inside the Vivaldi antenna.
Fig 1. LNA schematic.
Main specifications
Table 1. Bill of materials.
C1
C2
C3
C4
C5
C6
L1
L2
Q1
Q2
Table 1. Summary of the main LNA specifications.
Item
Symbol
Conditions
Gain
G
50-450MHz
∆G
50-450MHz
IRL
50-450MHz
6.5
dB
ORL
50-450MHz
19.5
dB
ISO
50-450MHz
27
dB
NF
50-450MHz
Te
50-450MHz
OP1dB
50-450MHz
(200-450MHz)
+12
(+18)
dBm
OIP3
50-450MHz
+30.5
dBm
OIP2
50-225MHz Input
(100-450MHz Output)
+42
dBm
Idd
Include LDO quiescent current
Vdd
Internal 3V LDO regulator
Gain
Variation
Input
Match
Output
Match
Reverse
Isolation
Noise
Figure
Noise
Temperature
Compression
point
3rd Order
Intercept Point
2nd Order
Intercept Point
Current
Consumption
Power Supply
Nom Min Max Unit
21.9
25.5
±1.8
dB
dB
0.5
dB
35
K
60
mA
3.5
30
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 150pF, 0603, GRM1885C1H151JA01
Murata, 100nF, 0603, GRM188R71H104KA93
AVX, 4.7uF, Case B, TAJB475K010RNJ
AVX, 1uF, Case B, TAJB105K035RNJ
Coilcraft, 1.2uF, 1008LS-122XJLB
Minicircuits, RF choke, ADCH-80A
RFMD, MMIC Amplifier, SPF-5122Z
National Semiconductors, LDO regulator, LP2950
Q1
RFin
C1
L1
C3
C4
RFout
DCin
C2
Q2
V
C5
L2
C6
Fig 2. Top view layout (Q2 is mounted on the bottom layer).
LNA with RFI (Medicina, May 2012)
RFI measurements performed with both SA and Power Meter
P (dBm)
45°
-0.8
E/W 135° N/S
-4.4 -10.6 -2.2
15dB below the
P1dB (@FM, 3V)
LNA for AAVS0 (June 2012)
32 LNA assembled and
tested for (active)
embedded pattern
measurement and/or
mutual coupling
LNA for AAVS0 (July 2012)
LNA for AAVS0 (July 2012)
LNA for AAVS0 (July 2012)
AAVS0 LNA housing
Conclusion
• LNA for both single antenna and
AAVS0 array measurements produced
and delivered on time
• For AAVS1 (500 pieces):
o Integration of 2 (and 3?) stage
o Integration of O-TX?
o LNA replication on PCB (FR4)
o Avoid the connectors?
o Different housing?
• For AAVS2 (min 7K pieces)
o Custom MMIC?
o Avoid the connectors!
o Different housing!
o Integration of O-TX?
Thanks!
LNA: S-parameters (1)
Meas. notes:
Equipment: HP8753C with HP85047 test set
Full 2 port Calibration, LNA Bias from port 2 of the VNA
LNA: S-parameters (2)
LNA: Noise measurements
Hot/Cold Load by Maury
• Best accuracy (+/- 3.5K vs +/-12K)
• Noise Source (re)calibration (ENR)
• More ENR points
(i.e. standard ENR table: 0.01, 0.1, 1, … GHz)
Meas. notes:
Hot/Cold Maury, Bias=3V , Tamb=297.4K
deducted switch with post processing
( reference plane = IN Connector)
LNA: Dynamic measurements
All measurements at: 3V, 58mA
 174mW
2-3 dB IP3 improvement at 5V, 90mA
 450mW!!

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