Nice try. While insulting again and again.
Just to satisfy your curiosity see attached. (my models are Cordels models for the Power mos))
Now, you will understand I stop any communication with you, with all due respect..
Attachments
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Fake seems to be the order of the day.
Lexington Man and Semiconductor Company Indicted for Theft of Trade Secrets | USAO-MA | Department of Justice
Raffi was after my time.
Only problem I have is your attitude and assuming you know what the answere is. It is not oscillating.
Appears to be heat sink to mounting plate interface is not thermally coupling good enough and I asked them to fix it. Other could be reversed diodes used for protection.... they are checking on that possibility. DaDod alerted me about that possibility.
I am sure, we will find the cause and be back on tract soon.
THx-RNMarsh
Thanks for the confirmation, 44 degrees phase margin, a disaster waiting to happen. And that's not even with the output close to the power rails.
For your education, given an N pole compensation schema (you are showing for N=2) there is still not much room to wiggle the ULGF while not affecting the stability margin. This is because audio amplifiers are by their nature minimum phase systems, therefore the magnitude and phase of the loop gain are not independent, you can get the phase(w) by simply applying a Hilbert transform to the gain(w). The only way to pull more loop gain from an audio amplifier, without pushing the ULGF to absurd values, is to use a higher order compensation network, a typical example would be the Cherry NDFL (which was practically used in the PGP amp). Or, in general, to use N poles followed by N-1 zeroes in the loop gain (to bring back the phase) and at the same time taking care of the sensitivity to stay within reasonable limits. I know of a couple of amplifier that are using N=5, one is an amazing small scale commercial class D amp, the other one was designed and build by a former member here (GK) as a proof of concept, but that one had other issues (was going berserk when approaching clipping).
And this is where the free lessons ends. For more, I can send you my hourly rate 😀.
BTW, there's no relationship between the gain/phase plots you are showing, it's like you are pulling rabbits from a hat. I'm sure you have more 😀.
Yes, I was making an educated guess, and I guess your guess is as good as my guess at this stage. I'm sorry if I upset you Richard and I apologize for the trouble.
P.S. Bob Cordell just posted this today, quite on topic I would think. You may find Bob Cordell more trustful than yours truly.
https://www.diyaudio.com/forums/sol...lls-power-amplifier-book-939.html#post5826115
Richard, the ignore button is great; it gets rid of sophomoric twits instantly.
1980 so I guess your youngest just missed it 🙂
My Eldest was given a beluga plushy for her first birthday by my CA dwelling sister. 3 months later she checked to see if we got the reference. When faced with blank looks she promptly sent us the CD. 22 years later and it's torturing me again 🙂
I was surprised how far two people with nerve can get, the fake IC problem is going to get worse before it gets better.
Speaking of knock-offs..
Does anyone in the trade know what kind of semi manufacturer is this one?
Coolaudio Semiconductors - COOLAUDIO International Ltd
Are they for real? Their website doesn't look like regular semiconductor manufacturer's website, rather more like hipster start-up.
They have various obsolete ICs in the program, including some by ADI..
Does anyone in the trade know what kind of semi manufacturer is this one?
Coolaudio Semiconductors - COOLAUDIO International Ltd
Are they for real? Their website doesn't look like regular semiconductor manufacturer's website, rather more like hipster start-up.
They have various obsolete ICs in the program, including some by ADI..
No idea, but it seems the getting things made on a small scale idea has translated over to IC's. Some of these functions are fairly obscure I don't know how there could be a substantial market.
There is always the possibility that people are simply copying masks from obsolete parts and running them in Taiwanese fabs. Pursuing theft of obsolete parts does not have a lot of financial incentive, except failures are returned through our QC department and become an annoyance. While I was working most of the fake stuff was still rebranded cheap parts, even occasionally empty packages.
Another point, with respect to ultra low noise bi-polars and JFET's I don't think there was any secret sauce or rocket science going on. A few motivated individuals could use well known principles to recreate something like the obsolete RHOM transistors and probably find a fab in China to produce them, if they could make any money doing it is another question.
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Just by curiosity, how a company like ADI can engage a fresh naturalised chinese guy,
just getting off the plane,(knowing the behavior of his native country in matter of patents and intellectual property) and let-him have access to sensitive informations ?
It looks like counter-spy services have tended to trap him, with the complicity of ADI, and that he had falling into it, as in a spy movie.
It doesn't work that way, if you profile employees even without the legal implications it is no way to run a business. We even had an engineer that laundered money for al-Qaeda on the side.
It looks strange to me. In europa, even for a native, if you are going to work in a 'sensitive' company, airports, Airbus indutry, Dassault system, any company that provide components or softwares for the army, Aero spatial etc. they make an enquiry on you and your family. And keep-you under surveillance.
I remember that, long time ago, when I was working in the R&D office of a hifi company, they had signed a contract with the army to provide intercom parts for tanks or submarines. We had to undergo such investigations while we were there before this contract was even under discussion.
Did you read the number of services involved in the charge of this Chinese? Even McGee and Abigail Sciuto (NCIS) were on the spot watching at his Google drive account, typing at the speed of light to break the firewall of his computer ;-)
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What about Gibbs? I posted another link years ago where NCIS stormed a warehouse full of fake ADI IC's destined for the Navy armed and in full flak jackets just like on TV.
I would not be so sure about that. Google "Szuhsiung Ho", "Xiaoxing Xi", and "Bo Jiang", these are only rather recent cases.
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I didn't say there isn't a problem, but what is a company to do? You could just not hire any Chinese citizens, but that might end up in a lawsuit. You might also put yourself at a competitive disadvantage if you presume there are talented applicants that will now work for your competitor. You could require security clearances, I suppose.
Still, it would just change the method of espionage. Instead of a Chinese national they would probably just find some disgruntled and unscrupulous employee they could bribe to bring them some files.
Economic espionage happens everywhere, and in all directions, and the US of A is not Mother Theresa. The only solution is to identify and survey high risk positions, don't put all eggs in the same Chinese basket, and be ready to mitigate the potential losses. I would think the US tech companies are doing a pretty good job, given the appetite for intellectual property theft in the Far East.
BTW, to my knowledge from another life, discrimination laws in EU were probably 10% of those in the politically correct North America. It was pretty common in the EU to specify a job with "only under 40 need to apply", try doing that in the US, even if ageism is otherwise blatant. I'm hearing things changed in the EU lately, which to me means only sweeping the true issue (ageism) under a thick rug of hypocrisy made in the USA.
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