L3-2ULNA
SPECIFICATIONS
Noise Figure: 0.8 dB nominal
Gain: 22 dB nominal
Frequency Range: 10-10.5 GHz
Input Voltage: 7 - 16 VDC
Current Drain: < 50 mA.
DESCRIPTION:
The L3-2ULNA is a low noise amplifier designed by W5LUA and Down East Microwave Inc.
using the latest PHEMPT technology. This LNA was designed for receive only purposes including,
EME, and other standard weak signal reception between 10 and 10.5 GHz. The LNA is
assembled in a machined chemical etched enclosure with SMA connectors only. It is biased
through the external DC feed through connector. This model is available as a board or complete
kit but not recommended unless you have suitable gain and noise fi gure measuring equipment.
INSTALLATION and USE:
Depending on your application, the LNA may be installed anywhere in your system to
increase gain. To maintain or improve the systems noise figure requires the LNA to be installed as
close to the systems antenna as possible. If you are using this LNA in a transceive system with
transmit bypass relays, be sure of their isolation characteristics and transmit power handling
capabilities before transmitting. Use only interconnecting cables and adapters that are rated for
use at or above 10 GHz. Inadequate cabling or cables with poor shielding may cause system
instabilities, signal loss, or undesirable intermittent operation.
The connector marked INPUT, is to be connected to the antenna. The OUTPUT is
connected to the receiver. The LNA requires protection from lightning or high static discharges.
The LNA will withstand input RF levels of up to 20 mW. Other precautions will need to be made
such as sequencing or protection against voltage spikes on the +DC line.
/Built/L3-2ULNA.doc 1 Rev. A 10/24/19
OPERATING:
Expected performance should be overall improvement in gain and noise figure of the
receive system with the LNA correctly installed. The proper installation of a LNA becomes more
and more important at these frequencies and because of out of band interference and high
insertion loss of all connection cables and connectors. The gain bandwidth of the LNA design is
wide to obtain a low noise figure. Therefore, certain conditions may cause overloading of your
receiver producing intermodulation. It is always suggested to use adequate filtering between gain
stages and to practice gain management by not cascading amplifiers to solve system noise
problems. Use of directional antennas will also increase desired signals and aid in elimination of
undesired signals.
/Built/L3-2ULNA.doc 2 Rev. A 10/24/19
C1 1.0pF 50 mil ATC
C9 1000pF (0805)
IC1 7660 SMD
C2 1000pF (0805)
Q1 CE351K2
C11 1.0pF 50 mil ATC
Q1 CE351K2
R8 1K pot SMD
C4 1000pF (0805)
C6 1.0pF 50 mil ATC
R3 1K pot SMD
C7 1000pF (0805)
D1 MMBD914
U1 78L05
IC 1
+
L3-2ULNA SCHEMATIC
+
INP UT
OUTPUT
C1
D
R2
C3
R3
D1
C12
R1
C2
R12
R5
C15
C13
C6
S
G
Q1
8
2
4
5
3
R11
C14
C5
C11
U1
R9
R4
R6
D
S
G
Q2
R10
D C IN PUT
IN
OUT
C4
C7
R7
R8
C8
C9
+
C10
COMPONENT LIST
All resistors are 1206 size chips unless indicated. The white band is positive on the Tantalum chip
capacitors. All other capacitors are various sizes.
R6 51Ω (0805)
C10 0.1µF
R7 470 Ω
C3 0.1µF
C12 4.7 µF Tant R1 51Ω (0805) R9 12Ω (0805)
C5 0.1µF C13 4.7 µF Tant R2 470Ω R10 51Ω (0805)
C14 4.7 µF Tant
R11 220Ω
C15 0.1µF R4 51Ω (0805) R12 5.1KΩ
C8 0.1µF
R5 240 Ω
/Built/L3-2ULNA.doc 3 Rev. A 10/24/19
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