Questions tagged [lna]

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Noise figure and bandwidth effect on signal jitter

I have an SNSPD based photodetector which produces short electrical pulses. The pulses have very short rise time Tr and a longer fall time Tf (the picture actually shows it the other way round but ...
Dictador's user avatar
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1 answer
115 views

Best type of switch for very small and sensitive signals

I have an H-bridge connected to a piezoelectric ceramic transducer which feeds it 40kHz 38V AC. After 3 full oscillations, it is stopped and it starts waiting for an echo, which is probably going to ...
epicMan123's user avatar
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1 answer
146 views

How to calculate power dissipation due to heat in an amplifer like LNA?

I'm trying to calculate how much power dissipated as heat in an amplifier like LNA. Let's say a HBT device operates at 4.8 V with 80 mA operating current. Gain of the amplifier is 25 dB, OP1dB = 16 ...
Aparna B's user avatar
  • 338
2 votes
1 answer
66 views

Output matching influences the input matching (RF amplifier)

Prerequisites I try to design a radio frequency low noise amplifier with a SiGe transistor (BFP740 infineon.) The amplifier is designed as a common emmiter with inductive degeneration. Observation ...
mjg's user avatar
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2 votes
1 answer
203 views

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 ...
JOAQUÍN PIÑEIRO's user avatar
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1 answer
129 views

Where does power entering at the LNA's output go when output return loss and reverse isolation are so low?

I am looking at the QPA2609 amplifier's datasheet. I noticed that the Output Return Loss is about -20 dB at 13 GHz and the reverse isolation is around -60 dB at 13 GHz. My understanding is that output ...
CMH12's user avatar
  • 181
2 votes
1 answer
659 views

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 ...
Dimitar Zhekov's user avatar
0 votes
1 answer
100 views

RF discrete transistor summing amplifier, adding RF pulses

I have a number of input lines (4-16 lines) on which RF pulses occur randomly on each line. I have to combine these lines into a single signal line. The pulses on each line are about 0.5ns wide and ...
Dictador's user avatar
1 vote
1 answer
199 views

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 ...
KJ7LNW's user avatar
  • 1,912
0 votes
1 answer
287 views

LNA saturation issues

I'm designing with LNA to receive a BW = 8 MHz signal (channel BW = 25 kHz), see block diagram: There is a case where an in-band channel signal (or blocker) which is strong enough saturates the LNA ...
Pascal R.'s user avatar
  • 107
11 votes
2 answers
1k views

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 ...
Asif Rahman's user avatar
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2 answers
116 views

LNA and DC amplification

In a THz detector, it produces a DC output voltage proportional to the input signal intensity. I need high SNR. My doubts are: Can I use LNA as a preamplifier? Is DC amplification possible with LNA? ...
prashanth's user avatar
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1 answer
184 views

GPS antenna not working

We are developing a GPS+LTE project based on the LE910S1-EAG module. We use a GPS LNA NJG1159PHH and an ACAG0301-1575 GPS antenna. In this module GNSS_LNA_EN is left open and GNSS_ANT_RF_OUT is ...
nirmal mathew's user avatar
0 votes
1 answer
219 views

DC voltage attenuation

I need to attenuate 0-5V to 0-1 mV. The output of simple voltage dividers (normal op amps or resistor divider) can't be distinguished from baseline noise (baseline noise is 10-20mV.) How can I ...
Mehran's user avatar
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1 answer
164 views

How can I place components of my amplifier design between the pads of an SMA connector?

I want to place some of my amplifier components between the pads of an SMA connector. Should I change some design rule or is the problem in the choice of the right footprint? I added an image of my ...
Sarah Ouerghemmi's user avatar
-1 votes
1 answer
111 views

LNA circuit: why is the inductor causing a voltage and current drop?

I am designing the following circuit whose schematic and testbench I put below: I performed a DC bias analysis. Theoretically, I would expect that at DC the inductor would be a short-circuit and the ...
Granger Obliviate's user avatar
2 votes
1 answer
1k views

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 ...
Granger Obliviate's user avatar
6 votes
2 answers
971 views

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 ...
lazba's user avatar
  • 171
0 votes
0 answers
51 views

By-passable LNA getting damaged

I am using ATEK951P4 in my design. As you know, this device can be switched between by-passable and LNA mode through control signal. The minimum required control voltage is 2V and maximum is 5V. I am ...
MightyBeard007's user avatar
0 votes
1 answer
131 views

Does anyone know the part number of this 900MHz LNA/PA front end IC?

Please see attached image. This IC is found on a 900MHz 802.15.4 wireless module, presumably working as LNA+PA, QFN16(?,not sure upon further inspection) package, with the following markings: 7 130 23 ...
Zhiyong Li's user avatar
1 vote
1 answer
85 views

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

What are the names of power supply connectors in this picture?
danyal's user avatar
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0 votes
2 answers
477 views

Active Antenna with Off The Shelf GPS Module

I'm trying to use an active antenna with the GY-GPSV3-NEO-M8N GPS module. In the hardware manual for NEO-M8N it is said that I need a DC bias circuit like shown in the picture below. As shown I need ...
Exclose's user avatar
  • 85
1 vote
1 answer
967 views

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 ...
Abhishek Chakraborty's user avatar
2 votes
0 answers
304 views

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 ...
Macuser's user avatar
  • 83
0 votes
1 answer
98 views

Selecting an amplifier - a PA or LNA that seem to have similar gains and P1db

I am using an SDR that outputs a maximum power of -25dBm. I need about 15dBm to go into the Tx antenna. I am looking at a PA and an LNA that have similar P1db points, but the LNA has a much better ...
szangvil's user avatar
1 vote
3 answers
367 views

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 ...
Codelearner777's user avatar
1 vote
1 answer
1k views

GPS antenna reference design

I have to put a GPS antenna on a PCB layout, but not sure how to calculate a matching network, and how to check that it will work correctly. I've chosen components with desired features (radiation ...
Denis Jelesniak's user avatar
0 votes
1 answer
259 views

Chaining Power Amplifiers

Problem I found an old (but not in use) garage door controller. The receiver is still intact but can't be reached from souterrain. The sender transmits a single tone on 27MHz in the citizen band. The ...
Ranunculum's user avatar
1 vote
0 answers
83 views

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. ...
Hansebenger's user avatar
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0 answers
71 views

Simulation of the injected noise to oscillator in Virtuoso

I have a differential LNA that injects current to an oscillator. I want to see the thermal noise injected to the oscillator. This noise is composed of the noise of oscillator + noise of the LNA. Now ...
Fateme's user avatar
  • 336
1 vote
1 answer
186 views

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's user avatar
  • 517
1 vote
0 answers
402 views

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 ...
SMALL's user avatar
  • 56
0 votes
1 answer
47 views

I cannot find information about some chips in 3 stage LNA circuit

Hi, here you can see 3-stage LNA circuit. I want to know information about two chips(6 pins) with R8 mark at the top. Also, 4 chips with D4 mark with 3 pins at right side. Is there anyone who has a ...
Tension's user avatar
1 vote
1 answer
334 views

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 ...
Meozaa's user avatar
  • 91
1 vote
1 answer
174 views

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 ...
user262213's user avatar
0 votes
0 answers
211 views

JFET LNA with High speed amplifier

In TI's LMH6518 datasheet, it shows a JFET LNA implementation: What's the purpose of C5, R17 and R49?
diverger's user avatar
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