What chip is used in this widely available generic LNA?

  • Context: Electronics 
  • Thread starter Thread starter Swamp Thing
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Discussion Overview

The discussion revolves around identifying the chip used in a widely available generic Low Noise Amplifier (LNA) board. Participants explore the potential components, seek documentation, and discuss the implications of using the LNA in various DIY projects, including concerns about performance metrics like P1dB and stability under mismatch conditions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires about the specific device used in generic LNA boards and requests an official datasheet for reference.
  • Another participant suggests that the device is likely a Field Effect Transistor and recommends examining the chip markings for identification.
  • There is speculation that documentation exists for similar boards, although it may not match exactly with the participant's board.
  • A participant notes that while evaluation module advertisements provide data, they often lack a specific part number, and mentions the possibility of a foreign clone of a known chip.
  • Concerns are raised about the P1dB specification and the stability of the amplifier under mismatch conditions, with one participant questioning the rationale for using an RF amplifier in such scenarios.
  • Another participant shares their experience with a different RF amplifier board that lacked markings but was identified through a video, expressing hope for a similar discovery for the current board.
  • Clarification is provided regarding the P1dB term, explaining it as the power level at which gain drops by 1 dB due to saturation.
  • One participant mentions difficulties in finding relevant information due to unrelated search results for the term "XR-601".

Areas of Agreement / Disagreement

Participants express uncertainty regarding the specific chip used in the LNA boards, and there is no consensus on the identification or documentation available. Multiple competing views on the nature of the device and its specifications remain present.

Contextual Notes

Limitations include the lack of clear markings on the device, potential variations in similar boards, and the dependence on external documentation that may not be directly applicable.

Swamp Thing
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Has anyone reverse engineered one of these generic LNA boards that you can buy from scores of online sources these days? What is the device used? I will be using this in some DIY projects so it would be nice to have an "official" datasheet as a baseline reference. For example, what is the P1db? Is it likely to be unconditionally stable under mismatch conditions?

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Probably a Field Effect Transistor.
There are numbers printed on it. Use a magnifying glass or microscope to read it, then look it up on-line.
 
I would assume someplace there is documentation that tells you specifically. Probably not the exact board you have but they are all likely doing something similar.
 
There is plenty of data with the evaluation module advertisements, but no part number.
Either read the text on the chip, or recognise the style of the evaluation PCB.
Maybe the rotated chip, and the text on the PCB = XR-601 is a clue.

Some foreign companies often replicate an evaluation board, designed by a Western manufacturer. A common target is ADI, since they provide Gerber files for their evaluation boards.

Maybe there is a foreign built LNA chip, a clone that does not quite meet the specs, being dumped as a cheap module that cannot be sold in any other way, without a liability.
 
Swamp Thing said:
For example, what is the P1db?
Sorry, where do you see that?

Swamp Thing said:
Is it likely to be unconditionally stable under mismatch conditions?
Why in the world would you try to use an RF amp under mismatched conditions?
 
The markings have been erased from the device on this
board.

I have an RF amplifier board of another kind which also doesn't have numbers on the devices, but luckily in that case someone had a unit with the numbers on and posted a video on YouTube with part numbers, schematic etc. I found the video by searching for the item title as posted on Amazon by various vendors. I am hoping to turn up something similar for the board in question.

berkeman said:
Sorry, where do you see that?
P1dB -- one dB compression point. The power level at which the gain drops by 1 dB due to saturation -- an indicator of the max power output it would deliver.

berkeman said:
Why in the world would you try to use an RF amp under mismatched conditions?
Could well happen when I connect an experimental receiving antenna to the input. Or an experimental mixer or something.

Baluncore said:
Maybe the ... XR-601 is a clue.
Kenwood makes an unrelated product called XR-601-1 which dominates the search results. If I search with "-kenwood", still no luck.
 
Last edited:

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