Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [lna]

32 questions
11
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2 answers

What does degree in a schematic mean when drawing a PCB?

I am designing a PCB for LNA with an SPF5189z. I found a reference schematic design in the SPF5189z datasheet: (Image excerpted from the previously linked datasheet.) What do they mean by those angles of 8.4° and 13.3°, etc? I know how to design a…
Asif Rahman
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2 answers

Why have a filter before the LNA in LoRa boards?

I've looked through some Semtech reference board schematics and found one strange thing: they put SAW filters both before and after the LNA. For example here is part from a Semtech reference board electrical schematic (1 and 2.) The same thing from…
lazba
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2
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1 answer

S parameters calculation from VNA file

I am trying to validate that our broadband LNA(Low noise amplifier) is working correctly. I wanted to measure the S21 of the LNA, I calibrated the VNA for the specified frequency range and measured performed a measurement. The file that I extracted…
Dimitar Zhekov
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2
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1 answer

Tips on how to increase the gain and lower the noise factor of a LNA

Hey guys I am designing a LNA biases by a 3.3 V source and tuned to 2.5 GHz. Here is the schematics, the testbench and some results (s parameters analysis). I would like to know if there is a way of increasing the gain and decreasing the noise…
Granger Obliviate
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2
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0 answers

Calibrating RTL-SDR Power with 50 Ohm Load and Thermal/LNA Noise

Ultimately I'm generating some spectrum plots in L-Band (1200-1800 MHz) and I need to get calibrated flux units (dBm/Hz) for my y-axis. I need a little assistance on creating this memo. I've been tasked to use simply a 50 ohm matched load followed…
Macuser
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1 answer

Noise Figure in LTSpice

I'm simulating an LNA from a paper. It's using HBT BiCMOS technology an one of the things the paper shows is the simulation of NF in range of 3GHz to 10GHz. I'm trying to replicate the simulation with LTSpice but as far as I know, only .noise…
JOAQUÍN PIÑEIRO
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1
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1 answer

How do you use an RC filter on an LNA output to reduce unwanted noise?

We designed two low noise amplifiers, one at 144 MHz and another at 440 MHz using this LNA; each design is tuned for the particular band. We noticed amplification at 440 MHz is clean and crisp, but amplification at 144 MHz is scratchy with FM audio…
KJ7LNW
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1
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1 answer

What are the names of power supply connectors in this picture?

What are the names of power supply connectors in this picture?
danyal
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1
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1 answer

Noise figure calculation in LTspice

I am a newbie in LTspice so the question can be seemed to be bit stupid, but I have build an LNA and now I want to calculate the noise figure of the system. I have run the .noise statement to calculate the noise density but is stuck with how to…
Abhishek Chakraborty
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vote
3 answers

What is the significance of phase margin in an open loop amplifier?

I know the importance of phase margin to ensure stability in closed loop systems, but what about in open loop systems? I am designing a regulated common based LNA IC that operates in open loop. Can we just ignore the phase response and just focus on…
Codelearner777
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Battery for LNA

I have recently gotten a LNA Ebay. It needs 12V 75mA. Since I want to measure 1kHz to 2MHz I am afraid of noise from a cheap Li-Ion 12V battery/powerbank which maybe has some noisy DC-DC converters. 9V block has insufficient voltage which maybe…
Hansebenger
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1
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1 answer

LNA circuit not working

I am trying to simulate a LNA circuit from the book "Design of CMOS RF Integrated Circuits and Systems" However, the LNA circuit still does not give POSITIVE GAIN. Any help ?
kevin
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Has anyone designed a low noise amplifier in the ISM band (24 GHz) using the discrete fet CEL CE3520K3?

I have been trying to design an LNA in the 24 GHz ISM band using CE3520K3. The FET is inherently unstable and one cannot use resistor loading at the input, resistive loading at the output, source inductor or drain gate feedback (RLC) circuit to…
SMALL
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1 answer

SDR Signal Generator Frontend

I am working on a board that can take the output of an SDR (or VCO) and provide high accuracy amplitude control (+- 0.5dB). This is an opensource project that I will hopefully launch on crowdsupply when its done :D. The final project will allow you…
Meozaa
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1
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1 answer

Matching Networks on Narrowband Multistage Low Noise Amplifier (LNA)

How does the inter-stage matching network of a narrowband LNA compare to that of a wideband LNA for the same multistage design? I've read somewhere that narrowband LNA does not necessarily require a matching network between the stages and can be…
user262213
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