TCA0372 shortage?...

On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail, and my
go-to floating ground generator is getting scarce. razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application). The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.

Sure, if it sits still. I\'d expect it to walk around a bit, what with
being a power op amp and all. ;) (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar. Then he came out with the
LM109/309.)

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
 
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs

Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.
 
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs

Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.
 
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s
all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with
the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

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
 
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s
all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with
the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

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
 
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s
all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with
the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

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
 
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.
 
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.
 
On 7/24/2020 3:41 PM, Phil Hobbs wrote:
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is
6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them
for DC
application and expect better and QC out a few boards that got a
real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that
it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The
motors
are inside some outer FB loop, and nobody cares about a 15-mV
offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what
with being a power op amp and all. ;)  (Widlar put a paper in the
ISSC one year that purported to prove that monolithic voltage
regulators with on-chip pass transistors were impossible due to
thermal feedback. Everybody believed it because it was Widlar.  Then
he came out with the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap,
the Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

Cheers

Phil Hobbs

My bad, that was Atari that code-named their product lines after
secretaries.

<https://en.wikipedia.org/wiki/Atari_8-bit_family#Development>
 
On 7/24/2020 3:41 PM, Phil Hobbs wrote:
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is
6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them
for DC
application and expect better and QC out a few boards that got a
real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that
it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The
motors
are inside some outer FB loop, and nobody cares about a 15-mV
offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what
with being a power op amp and all. ;)  (Widlar put a paper in the
ISSC one year that purported to prove that monolithic voltage
regulators with on-chip pass transistors were impossible due to
thermal feedback. Everybody believed it because it was Widlar.  Then
he came out with the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap,
the Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

Cheers

Phil Hobbs

My bad, that was Atari that code-named their product lines after
secretaries.

<https://en.wikipedia.org/wiki/Atari_8-bit_family#Development>
 
On 7/24/2020 3:41 PM, Phil Hobbs wrote:
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is
6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them
for DC
application and expect better and QC out a few boards that got a
real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that
it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The
motors
are inside some outer FB loop, and nobody cares about a 15-mV
offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what
with being a power op amp and all. ;)  (Widlar put a paper in the
ISSC one year that purported to prove that monolithic voltage
regulators with on-chip pass transistors were impossible due to
thermal feedback. Everybody believed it because it was Widlar.  Then
he came out with the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap,
the Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

Cheers

Phil Hobbs

My bad, that was Atari that code-named their product lines after
secretaries.

<https://en.wikipedia.org/wiki/Atari_8-bit_family#Development>
 
On 7/24/2020 3:41 PM, Phil Hobbs wrote:
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is
6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them
for DC
application and expect better and QC out a few boards that got a
real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that
it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The
motors
are inside some outer FB loop, and nobody cares about a 15-mV
offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what
with being a power op amp and all. ;)  (Widlar put a paper in the
ISSC one year that purported to prove that monolithic voltage
regulators with on-chip pass transistors were impossible due to
thermal feedback. Everybody believed it because it was Widlar.  Then
he came out with the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap,
the Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

Cheers

Phil Hobbs

My bad, that was Atari that code-named their product lines after
secretaries.

<https://en.wikipedia.org/wiki/Atari_8-bit_family#Development>
 
On 7/24/2020 3:41 PM, Phil Hobbs wrote:
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is
6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them
for DC
application and expect better and QC out a few boards that got a
real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that
it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The
motors
are inside some outer FB loop, and nobody cares about a 15-mV
offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what
with being a power op amp and all. ;)  (Widlar put a paper in the
ISSC one year that purported to prove that monolithic voltage
regulators with on-chip pass transistors were impossible due to
thermal feedback. Everybody believed it because it was Widlar.  Then
he came out with the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap,
the Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

Cheers

Phil Hobbs

My bad, that was Atari that code-named their product lines after
secretaries.

<https://en.wikipedia.org/wiki/Atari_8-bit_family#Development>
 
On 7/24/2020 3:41 PM, Phil Hobbs wrote:
On 2020-07-24 19:37, bitrex wrote:
On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is
6-1/2 months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset
voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them
for DC
application and expect better and QC out a few boards that got a
real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that
it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA
would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The
motors
are inside some outer FB loop, and nobody cares about a 15-mV
offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what
with being a power op amp and all. ;)  (Widlar put a paper in the
ISSC one year that purported to prove that monolithic voltage
regulators with on-chip pass transistors were impossible due to
thermal feedback. Everybody believed it because it was Widlar.  Then
he came out with the LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap,
the Lauren didn\'t pan out. To the crushing-stump with it.

You really are a very strange person.

Cheers

Phil Hobbs

My bad, that was Atari that code-named their product lines after
secretaries.

<https://en.wikipedia.org/wiki/Atari_8-bit_family#Development>
 
On 7/24/2020 4:53 PM, John Larkin wrote:
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.

Seems like the kind of guy who had more than one girl friend. Like Feynman
 
On 7/24/2020 4:53 PM, John Larkin wrote:
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.

Seems like the kind of guy who had more than one girl friend. Like Feynman
 
On 7/24/2020 4:53 PM, John Larkin wrote:
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.

Seems like the kind of guy who had more than one girl friend. Like Feynman
 
On Fri, 24 Jul 2020 17:24:38 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 4:53 PM, John Larkin wrote:
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.


Seems like the kind of guy who had more than one girl friend. Like Feynman

She was living with him in Puerta Viallarta (sp?) and back visiting
her mom. She was worried about his drinking.

He had a tablecloth on the kitchen table with IC drawings under it.
She was NOT allowed to look at them.

She was surprised that we had heard of him. She had no idea what he
did.
 
On Fri, 24 Jul 2020 17:24:38 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 4:53 PM, John Larkin wrote:
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.


Seems like the kind of guy who had more than one girl friend. Like Feynman

She was living with him in Puerta Viallarta (sp?) and back visiting
her mom. She was worried about his drinking.

He had a tablecloth on the kitchen table with IC drawings under it.
She was NOT allowed to look at them.

She was surprised that we had heard of him. She had no idea what he
did.
 
On Fri, 24 Jul 2020 17:24:38 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 4:53 PM, John Larkin wrote:
On Fri, 24 Jul 2020 19:37:41 -0400, bitrex <user@example.net> wrote:

On 7/24/2020 2:46 PM, Phil Hobbs wrote:
On 2020-07-24 14:16, John Larkin wrote:
On Thu, 23 Jul 2020 21:29:40 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-07-23 20:28, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 02.14.39 UTC+2 skrev bitrex:
On 7/23/2020 7:47 PM, Lasse Langwadt Christensen wrote:
fredag den 24. juli 2020 kl. 01.12.21 UTC+2 skrev bitrex:
On 7/23/2020 7:01 PM, Lasse Langwadt Christensen wrote:
torsdag den 23. juli 2020 kl. 20.15.24 UTC+2 skrev Phil Hobbs:
ON still lists the TCA0372 power op amp as active, but total
distributor
stock is less than 1k pieces and the quoted lead time is 6-1/2
months!

Here I\'m trying to hang a couple of ADA4817s off a 20-V rail,
and my
go-to floating ground generator is getting scarce.
razzafrazza%$&@!!


for 20V wouldn\'t this be an alternative?

https://www.st.com/resource/en/datasheet/l2720w.pdf


Looks good but they seem a bit un-confident about the offset voltage
spec...???? it\'s usually somewhere in there

page5: input offset voltage -/+10mV ?


Right. The TCA0372 lists 1mV typ and 15 mV max, when there\'s a wide
spread there I get the impression that the 15mV parts are the real
outlier and don\'t show up much in practice. You could use them for DC
application and expect better and QC out a few boards that got a real
bad one.

When it\'s just -/+10 mV with no typ I get the impression that it\'s all
over the place from device to device, so might not be the best
choice of
part for a DC-coupled application with gain.

But interpreting datasheets can be mysterious, I\'d guess the TCA would
not be so popular if it were giving offsets at the far end
routinely though.

but max might happen, less than 10mV is better than usually 1mV
occupationally 15mV, you have to design for it unless you want to
start sorting


Beasts like that are (IME) used for things like driving servomotors or
making floating ground/supply rails (my usual application).  The motors
are inside some outer FB loop, and nobody cares about a 15-mV offset on
a supply rail.

For the occasional precision application, wrap a chopamp feedback loop
round it.

Or just calibrate out the offset.


Sure, if it sits still.  I\'d expect it to walk around a bit, what with
being a power op amp and all. ;)  (Widlar put a paper in the ISSC one
year that purported to prove that monolithic voltage regulators with
on-chip pass transistors were impossible due to thermal feedback.
Everybody believed it because it was Widlar.  Then he came out with the
LM109/309.)

Cheers

Phil Hobbs


Maybe Widlar believed it too for a while, hard to say. I get the
impression a lot of his designs didn\'t immediately work as expected
which is why he carried a sledge hammer I feel the same way sometimes.

I expect they were mostly named after whomever the sexiest secretaries
in the National office was as was the fashion at the time. Aw crap, the
Lauren didn\'t pan out. To the crushing-stump with it.

We met his girlfriend at the bar of the Washington Square Bar and
Grille. I can\'t remember her name.


Seems like the kind of guy who had more than one girl friend. Like Feynman

She was living with him in Puerta Viallarta (sp?) and back visiting
her mom. She was worried about his drinking.

He had a tablecloth on the kitchen table with IC drawings under it.
She was NOT allowed to look at them.

She was surprised that we had heard of him. She had no idea what he
did.
 

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