WHAT ARE THE DESIGN PROCEDURE FOR LNA

Thread Starter

OMORU

Joined Apr 27, 2021
7
GOOD MORNING ALL, I AM NEW IN CIRCUIT DESIGN I WANT TO BUILD AN LNA USING MOSFET, I WANT TO KNOW THE DESIGN PROCEDURE AND HOW TO CALCULATE THE VALUES OF RESISTORS, INDUCTORS AND CAPACITORS FOR INPUT AND OUTPUT IMPEDANCE MATCHING NETWORK. THANK YOU
 

Janis59

Joined Aug 21, 2017
1,350
Och, oum. The same way as every transistor circuit, but taking in account the impedance and matching. And if for general circuit there are no way better modelling soft as LT-Spice, then for specifically RF upper end there are no way better soft as RF-Sim-99.
 

Thread Starter

OMORU

Joined Apr 27, 2021
7
Och, oum. The same way as every transistor circuit, but taking in account the impedance and matching. And if for general circuit there are no way better modelling soft as LT-Spice, then for specifically RF upper end there are no way better soft as RF-Sim-99.
THANK YOU VERY MUCH SIR, I WANT TO DO A CO DESIGN OF THE LNA AND ANTENNA BUT WITH THE LT SPICE THIS WILL NOT BE POSSIBLE ALSO .. KINDLY ADVICE SIR
 

Janis59

Joined Aug 21, 2017
1,350
RE:""i have not designed any transistor circuit before"" thatswhy I begun my reply with shout of extreme surprize. So I shall speak it loud - please not take it insulting, please, it is just the very very good advice: never buy Your first vehicle in life Ferrari, never build Your first handmade aircraft the Boeing, and never begin Your electronics designer experience with highest pilotage like LNA. Begin with moderate simple things, and if You shall learn to make thinking via the soldering hammer tip, You soon will be able to make even LNA. But not as the first construction into life. Just, without a good VNA and modelling skills and sense of PCB geometry in terms of EM volatiles it will give only disappointment. It all will come within a proper time. By the way, Warmly recommend to read two books, each two volume by 1000 pages, first is Titze&Schenk and other is Horowitz&Hill. After many things will become clear by itself. Those both books have a zillions cracked copies at all around the world, even nearer than dark-web.
 

Thread Starter

OMORU

Joined Apr 27, 2021
7
RE:""i have not designed any transistor circuit before"" thatswhy I begun my reply with shout of extreme surprize. So I shall speak it loud - please not take it insulting, please, it is just the very very good advice: never buy Your first vehicle in life Ferrari, never build Your first handmade aircraft the Boeing, and never begin Your electronics designer experience with highest pilotage like LNA. Begin with moderate simple things, and if You shall learn to make thinking via the soldering hammer tip, You soon will be able to make even LNA. But not as the first construction into life. Just, without a good VNA and modelling skills and sense of PCB geometry in terms of EM volatiles it will give only disappointment. It all will come within a proper time. By the way, Warmly recommend to read two books, each two volume by 1000 pages, first is Titze&Schenk and other is Horowitz&Hill. After many things will become clear by itself. Those both books have a zillions cracked copies at all around the world, even nearer than dark-web.
Thank you very much sir
 

Papabravo

Joined Feb 24, 2006
16,835
This is a very poor choice for a first project. There is a great deal you need to learn about circuits in general and RF design in particular. You'll get there eventually, but not in the short term. There is an apocryphal saying among astronomers, that if you wan to make a 12-foot (diameter) mirror so you can see things that are very far away you will get to the goal quicker by starting with a 2-foot (diameter) mirror. In case you missed the point - it is that the things you learn on your first project will actually get you there faster and will most certainly not be a waste of time.
 
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Janis59

Joined Aug 21, 2017
1,350
Bertus, as I told, both books are available in thousand of thousands places. But, as many countries free books is something for what to sit into prison, You should not ask me a precise guiding, sorry. Here are links to both books at Amazon as fully legal (but unavailable because of the price) resource - https://www.springer.com/gp/book/9783540786559 and https://www.bookdepository.com/Art-...YyN_kEpjlv12xJuGWK6C1Jr9bXQA62LxoCXL4QAvD_BwE

For my opinion, first book is best for understanding the theory basics and calculation fundamentals, whilst second is better for understanding the circuitry, topology, practical questions. And Yes, You identified it correctly.
 

Thread Starter

OMORU

Joined Apr 27, 2021
7
I clearly understand and appreciate all the suggestions and mentioned comments. I am under pressure to do a simulation of LNA using double gate MOSFET I tried searching for double gate MOSFET transistor in the ADS design kits but could not find any can somebody please tell me an alternative to this in the ADS software... Let me settle this first I will follow your suggestions and see how to download the suggested books Thank you Seniors
 

Papabravo

Joined Feb 24, 2006
16,835
I clearly understand and appreciate all the suggestions and mentioned comments. I am under pressure to do a simulation of LNA using double gate MOSFET I tried searching for double gate MOSFET transistor in the ADS design kits but could not find any can somebody please tell me an alternative to this in the ADS software... Let me settle this first I will follow your suggestions and see how to download the suggested books Thank you Seniors
I remember working with such a part almost 50 years ago. They were extremely static sensitive and came with a shorting wire on the leads to prevent accidental potential differences being applied in handling. The circuit I was working with never worked and I haven't had occasion to use one since. The reason you might be having trouble finding information could be because there is non available. Do you know for a fact that anybody still makes such a part? Have you checked with any large distributors like Digi-key or Mouser?

Here is one of the top Google Hits:

https://www.onsemi.com/pdf/datasheet/en4423-d.pdf

I guess you didn't try very hard. Digi-key has them marked obsolete and has no stock. Mouser has 37 pieces and has them marked obsolete. Here is the quite:
End of Life: Scheduled for obsolescence and will be discontinued by the manufacturer.

I would say it looks pretty grim.

I checked LTspice and there do not appear to be any Dual Gate MOSFET models. I will check further.
There is this thread from 4 years ago:

https://forum.allaboutcircuits.com/threads/dual-gate-mosfet-model-for-ltspice.131162/

This is the one I worked with 50 years ago

https://www.alldatasheet.com/view.jsp?Searchword=40673

@Bordodynov has a large library of SPICE models and as it happens there are a dozen or so that you can choose from. His library can be downloaded from here:

http://bordodynov.ltwiki.org/

The one you want is the 16 M is the first one listed at 16 Meg. Of course you will also need LTspice to use that library. There are example circuits using the:
  1. BF992
  2. BF998
  3. BF981
  4. BF994S
  5. 3SK292 - which has multiple examples
As near as I can tell from a cursory examination the 3SK292 is the only part which is still readily available - at least in the USA.
 
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