Another way: everytime you double the number of parallel devices, the voltage noise drops by about 30%.
So it gets useless fast - going from 32 to 64 devices drops it just the same factor as when you went from 1 to 2.
Jan
So it gets useless fast - going from 32 to 64 devices drops it just the same factor as when you went from 1 to 2.
Jan
Jan, you need to express this in dB's. Then you really see the point.
My RIIA stage uses 8 BC5xx transistors in parallel = SQR(8) = 2.8 = 9 dB
My RIIA stage uses 8 BC5xx transistors in parallel = SQR(8) = 2.8 = 9 dB
Well the point is that the result is the same no matter how you express it.
8 devices is 2^3 means 3 times -3db is a 9db gain in S/N as you say.
Since -3dB is a factor 0.7 it is also 3 times taking the 0.7 times factor which is 0.343 or 1/2.9 which of course is -9.3dB (but I'll buy -9dB).
You can't fool nature by manipulating units ;-)
Jan
8 devices is 2^3 means 3 times -3db is a 9db gain in S/N as you say.
Since -3dB is a factor 0.7 it is also 3 times taking the 0.7 times factor which is 0.343 or 1/2.9 which of course is -9.3dB (but I'll buy -9dB).
You can't fool nature by manipulating units ;-)
Jan
If you are logged in, go to post #254 and hover your pointer over the large J at the left.
Then look near the bottom of the pop up window for the "start conversation" button.
Then look near the bottom of the pop up window for the "start conversation" button.
Seems it is less active at TI since 2022 perhaps when I click in his profile and go to his private web page.
Too bad, he has given a lot of good ic at TI. I hope it will come back soon.
I was going to ask him not to pollute much his thread if he has at TI an internal tool to look for a list of op amps in the long catalog with inverted input pins with less than 100R impedance else than the one we always work with. The web site filter are too much restrictive and google didn't helped that much.
Too bad, he has given a lot of good ic at TI. I hope it will come back soon.
I was going to ask him not to pollute much his thread if he has at TI an internal tool to look for a list of op amps in the long catalog with inverted input pins with less than 100R impedance else than the one we always work with. The web site filter are too much restrictive and google didn't helped that much.
thanks Rayma, I am to try rigth now ! 🙂
Edit : seems the PM option was not enabled by him.
@MikeHatsome if you hear me (Tommy from The Who pun intended ). But it seems message alert with @id alert into the posts are tied with the PM options allowed or not by each member. I concllude this because the id helping discover feature doesn't appear when I type @mikeh...
Edit : seems the PM option was not enabled by him.
@MikeHatsome if you hear me (Tommy from The Who pun intended ). But it seems message alert with @id alert into the posts are tied with the PM options allowed or not by each member. I concllude this because the id helping discover feature doesn't appear when I type @mikeh...
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Appears johnc124 has retired.
"In early 2022, after leading a very large business and the entire Tucson site through the pandemic and a very challenging semiconductor shortage, I decided to take some time off to get back to what I love: hands-on electrical engineering. This website is a result of my time off and I plan to keep growing it in the future with lots of interesting content. So stay tuned!
— John Caldwell"
"In early 2022, after leading a very large business and the entire Tucson site through the pandemic and a very challenging semiconductor shortage, I decided to take some time off to get back to what I love: hands-on electrical engineering. This website is a result of my time off and I plan to keep growing it in the future with lots of interesting content. So stay tuned!
— John Caldwell"
Yeah, Post Pandemic " wild nature call" syndrom 😊
That's fine. He brings so much for audio community 🙂 ! Very involved guy.
That's fine. He brings so much for audio community 🙂 ! Very involved guy.
Stuart Yaniger and I visited him just before the full restructure of TI Tucson. What they then charged him with to get done.
He looks like your average guy. Until he starts to speak.
His IQ must be through the roof, as are his social skills and sensitivity.
The type of guy that quickly floats to the top level no matter where he gets involved.
A visit I will always remember.
Jan
I assume that increasing the drain current in the small-signal mode is always beneficial because the highest linearity is achieved in this range. Moreover, in small-signal applications, the fundamental noise is determined by the first stage. The higher the gain of the first stage, the lower the noise referred to the input. And although, according to the datasheet, the optimal noise current for this transistor is 5 mA, the increase in transconductance at higher currents may result in a greater effect than the increase in noise.
Ray, do you have a link to this website?
His LinkedIn profiles says that after the one year sabbatical he's back at TI as 'Technologist' .
https://www.linkedin.com/in/john-caldwell-851b41a4/
Edit: found it: https://www.soundanalog.com/
Jan
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Good that he back at TI. I think "Technologist" implies that he has free rein - a sort of sand pit for the super talented. Hope that is the case.
Craig
Craig
While a title like 'Technologist' or 'Fellow' brings prestige and some autonomy, including direct reporting to a higher level of management (and thus distance day-to-day new product activities), my observation is that it often results in lots of 'special assignments' related to coordinating, planning, oversight of others' projects, etc. All that can be time-intensive and reduce playtime in one's intended sandbox.