Speaking of high speed opamps

[Rick C]

On Sunday, March 8, 2020 at 11:46:20 AM UTC-4, Don Kuenz wrote:

plastcontrol.ru@gmail.com wrote:

And here's a new page about coping with COVID-19 (Coronavirus):

https://crcomp.net/biology/covid19

Thank you,

--
Don Kuenz KB7RPU

The page says one thing that is not correct. "Numbers are low in the US because of the public health measures we’ve implemented". Numbers are low in the US be cause like in many places we were not prepared for this and we are not testing very many people. The Federal government isn't allowing testing for COVID-19 unless you meet strict criteria which means they aren't really looking for community based spreading. So we have some significant number of infected that we can't report because we aren't testing them. These people continue to spread the disease raising our infection numbers in spite of our efforts to contain the disease.

We had a chance to stop this thing early on. But we failed to take appropriate measures. Now it is moving quickly enough we may not be able to get in front of it.

--

Rick C.

-+ Get 1,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209

 

[Phil Hobbs]

On 2020-03-07 23:01, Winfield Hill wrote:

Phil Hobbs wrote...

For applications that aren't too noise sensitive,
I'm a fan of LT6171/6172.

LM6171, LM6172.


Linear, National, what's the difference.

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

On 2020-03-07 18:39, jlarkin@highlandsniptechnology.com wrote:

On Sat, 7 Mar 2020 10:54:43 -0800 (PST), George Herold
ggherold@gmail.com> wrote:

On Friday, March 6, 2020 at 8:53:20 PM UTC-5, Winfield Hill wrote:
George Herold wrote...

I'm putting together an order for some fast opamps.

The x-Chapters, Tables 4x.2 (VFB, 4-pages), and 4x.3
(CFB), with accompanying discussions, pages 304-323.
Yeah my table 4x.2 has all sorts of pencil marks on it.

So here's thing I see. All the low noise parts (v_n<~2 nV/rtHz)
have crappy slew rate... fast slew rate = more front end noise.
Is there a 'electronics' reason for that or is it maybe market
forces. (no needs low noise and slew rate)

High slew rate does suggest big voltage swings! So noise doesn't
matter much. In what I think is your case, only the last stage needs
big swing and high slew. Keep its gain moderate.

Current-mode opamps are inherently cruddy for noise and DC
performance. They are deceptive in that they steal a lot of power from
the input signal as speeds go up; that's one way to get slew rate!

They're crap for DC performance, but if you can stand the dissipation,
they can be pretty good for noise in noninverting mode.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

Rick C <gnuarm.deletethisbit@gmail.com> wrote in
news:3fff5e2f-4db5-4c84-9da8-b44b02e782ca@googlegroups.com:

On Sunday, March 8, 2020 at 11:46:20 AM UTC-4, Don Kuenz wrote:
plastcontrol.ru@gmail.com wrote:

And here's a new page about coping with COVID-19 (Coronavirus):

https://crcomp.net/biology/covid19

Thank you,

--
Don Kuenz KB7RPU

The page says one thing that is not correct. "Numbers are low in
the US because of the public health measures we’ve implemented".
Numbers are low in the US be cause like in many places we were
not prepared for this and we are not testing very many people.
The Federal government isn't allowing testing for COVID-19 unless
you meet strict criteria which means they aren't really looking
for community based spreading. So we have some significant number
of infected that we can't report because we aren't testing them.
These people continue to spread the disease raising our infection
numbers in spite of our efforts to contain the disease.

We had a chance to stop this thing early on. But we failed to
take appropriate measures. Now it is moving quickly enough we may
not be able to get in front of it.

Your "news" is old and now incorrect. The "criteria" has changed.

But yeah... we have no clue about where it is or how much...
here.

 

[Rick C]

On Monday, March 9, 2020 at 9:36:23 AM UTC-4, DecadentLinux...@decadence.org wrote:

Rick C <gnuarm.deletethisbit@gmail.com> wrote in
news:3fff5e2f-4db5-4c84-9da8-b44b02e782ca@googlegroups.com:

On Sunday, March 8, 2020 at 11:46:20 AM UTC-4, Don Kuenz wrote:
plastcontrol.ru@gmail.com wrote:

And here's a new page about coping with COVID-19 (Coronavirus):

https://crcomp.net/biology/covid19

Thank you,

--
Don Kuenz KB7RPU

The page says one thing that is not correct. "Numbers are low in
the US because of the public health measures we’ve implemented"..
Numbers are low in the US be cause like in many places we were
not prepared for this and we are not testing very many people.
The Federal government isn't allowing testing for COVID-19 unless
you meet strict criteria which means they aren't really looking
for community based spreading. So we have some significant number
of infected that we can't report because we aren't testing them.
These people continue to spread the disease raising our infection
numbers in spite of our efforts to contain the disease.

We had a chance to stop this thing early on. But we failed to
take appropriate measures. Now it is moving quickly enough we may
not be able to get in front of it.


Your "news" is old and now incorrect. The "criteria" has changed.

But yeah... we have no clue about where it is or how much...
here.

The criteria may have changed, but it still does not provide for enough testing to find those who are spreading the disease. Having 1 or 1.5 or 2 million test kits available is great, but not of much use if they aren't used. Waiting for symptoms to show up isn't going to stop the spread.

I won't say anymore about this hear. I don't want to trash the thread with off topic stuff we can discuss elsewhere.

--

Rick C.

+- Get 1,000 miles of free Supercharging
+- Tesla referral code - https://ts.la/richard11209

 

[Winfield Hill]

Rick C wrote...

The criteria may have changed, but it still does not provide
for enough testing to find those who are spreading the disease.
Having 1 or 1.5 or 2 million test kits available is great ...

I think the're being careful with the language. Each test kit
can test something like 400 (384?) people, so when they say 1M
tests (not 1M test kits), that's only 25,000 kits. I suspect
when they run the kit, you get to test the number of samples
filling the plate. So if you require an immediate result,
you have to run it with a small number of wells filled.


--
Thanks,
- Win

 

[Winfield Hill]

Phil Hobbs wrote...

On 2020-03-07 23:01, Winfield Hill wrote:
Phil Hobbs wrote...

For applications that aren't too noise sensitive,
I'm a fan of LT6171/6172.

LM6171, LM6172.

Linear, National, what's the difference.

I like the LT1361 and 62 opamps. All of these
are what I call CFB+VFB, with an internal CFB
stage creating super-fast slewing, high-Z inputs
and a high gain-bandwidth VFB mode.


--
Thanks,
- Win

 

[George Herold]

On Saturday, March 7, 2020 at 11:01:53 PM UTC-5, Winfield Hill wrote:

Phil Hobbs wrote...

For applications that aren't too noise sensitive,
I'm a fan of LT6171/6172.

LM6171, LM6172.

Right. The only one with more slew rate of the VFB's in your table is the
LM7171 Both much to fast for me. :^)

George H.

--
Thanks,
- Win