It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I can't think of one. The design is 56 years old. It has its own
Wikipedia page.
There are faster, cheaper, lower noise, lower bias current/offset RRIO
amps around these days.
I remember the day when, still a kid in college, I decided to replace
LM709s with LM741s in a control system. The 741s were more expensive
(the cost of a pretty good lunch) but didn't need external
compensation parts or front-end-zener protection, and current limited.
The early 741s had bad popcorn noise, but I'd expect that to be better
now.
My default gumdrop amp is OPA197 now, in SOT23. It makes a good
comparator too. There are cheaper parts if you can tolerate low supply voltages.
john larkin <JL@gct.com> wrote:
On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I can't think of one. The design is 56 years old. It has its own
Wikipedia page.
There are faster, cheaper, lower noise, lower bias current/offset RRIO
amps around these days.
I remember the day when, still a kid in college, I decided to replace
LM709s with LM741s in a control system. The 741s were more expensive
(the cost of a pretty good lunch) but didn't need external
compensation parts or front-end-zener protection, and current limited.
The early 741s had bad popcorn noise, but I'd expect that to be better
now.
My default gumdrop amp is OPA197 now, in SOT23. It makes a good
comparator too. There are cheaper parts if you can tolerate low supply
voltages.
LM358s are still useful, though. I use them in things like bias loops,
where their limited speed and fairly poor input accuracy don’t matter.
In our licensing conversations, pointing out that we’re saving more on the >BOM than the royalty costs is a pretty persuasive argument, entirely aside >from the improved performance.
Cheers
Phil Hobbs
On Sun, 3 Nov 2024 19:14:54 -0000 (UTC), Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
john larkin <JL@gct.com> wrote:
On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I can't think of one. The design is 56 years old. It has its own
Wikipedia page.
There are faster, cheaper, lower noise, lower bias current/offset RRIO
amps around these days.
I remember the day when, still a kid in college, I decided to replace
LM709s with LM741s in a control system. The 741s were more expensive
(the cost of a pretty good lunch) but didn't need external
compensation parts or front-end-zener protection, and current limited.
The early 741s had bad popcorn noise, but I'd expect that to be better
now.
My default gumdrop amp is OPA197 now, in SOT23. It makes a good
comparator too. There are cheaper parts if you can tolerate low supply
voltages.
LM358s are still useful, though. I use them in things like bias loops,
where their limited speed and fairly poor input accuracy donÂ’t matter.
In our licensing conversations, pointing out that weÂ’re saving more on the >> BOM than the royalty costs is a pretty persuasive argument, entirely aside >> from the improved performance.
Cheers
Phil Hobbs
358 is not bad, a dual opamp for 10 cents, but most have some shared
current sources that can make sections interact. And weird behavior if
any input goes slightly below ground.
On Sun, 03 Nov 2024 18:07:35 +0000, Cursitor Doom <cd@notformail.com>
wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I can't think of one. The design is 56 years old. It has its own
Wikipedia page.
There are faster, cheaper, lower noise, lower bias current/offset RRIO
amps around these days.
I remember the day when, still a kid in college, I decided to replace
LM709s with LM741s in a control system. The 741s were more expensive
(the cost of a pretty good lunch) but didn't need external
compensation parts or front-end-zener protection, and current limited.
The early 741s had bad popcorn noise, but I'd expect that to be better
now.
My default gumdrop amp is OPA197 now, in SOT23. It makes a good
comparator too. There are cheaper parts if you can tolerate low supply voltages.
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
On 11/3/24 23:10, Jeroen Belleman wrote:
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
Jeroen Belleman
On 11/3/24 23:10, Jeroen Belleman wrote:
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
Jeroen Belleman
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
On Sun, 3 Nov 2024 23:17:55 +0100, Jeroen Belleman
<jeroen@nospam.please> wrote:
On 11/3/24 23:10, Jeroen Belleman wrote:
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
Jeroen Belleman
The early integrated PNPs had betas in the single digits, so a bit of radiation poisoning was no big deal.
I still have a 747 in a box somewhere.
Jan Panteltje <alien@comet.invalid> wrote:
[...]
I still have a 747 in a box somewhere.
How could you loose anything that size?
On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
On 11/3/24 23:10, Jeroen Belleman wrote:
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
Jeroen Belleman
Have to go back to Jim Thompson's MC1530 era to get that:
<http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>
Jan Panteltje <alien@comet.invalid> wrote:
[...]
I still have a 747 in a box somewhere.
How could you loose anything that size?
On Sun, 3 Nov 2024 22:24:12 -0500, bitrex <user@example.net> wrote:
On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
On 11/3/24 23:10, Jeroen Belleman wrote:
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
Jeroen Belleman
Have to go back to Jim Thompson's MC1530 era to get that:
<http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>
He probably designed that without Spice.
The first IC opamp I tried was made by GE. All NPN, with an internal
zener in the level-shift part. It was amazingly noisy.
I designed some little baby-board opamps, all TO-92 transistors and folded-over axial parts. By selecting some resistors we got sub 1 mV
offset and under 1 uV/degC, but it was tedious.
I still have some Philbrick opamps that I found at a flea market.
https://www.dropbox.com/scl/fi/tujdcjpvv7m4b2yo8w751/Philbricks.jpg?rlkey=19ivv2tgqmqiy9ci92lgysrz7&raw=1
On 11/4/2024 10:21 AM, john larkin wrote:
On Sun, 3 Nov 2024 22:24:12 -0500, bitrex <user@example.net> wrote:
On 11/3/2024 5:17 PM, Jeroen Belleman wrote:
On 11/3/24 23:10, Jeroen Belleman wrote:
On 11/3/24 19:07, Cursitor Doom wrote:
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in >>>>>> certain niche applications in 2024?
I've used them in power supply regulators exposed to radiation.
Being old designs and all-NPN, they're pretty rad-hard.
Jeroen Belleman
Blimey, I just checked: It isn't all-NPN! Fortunately
for me, it still kept working under irradiation...
Jeroen Belleman
Have to go back to Jim Thompson's MC1530 era to get that:
<http://www.elektronikjk.com/elementy_czynne/IC/MC1530-2.pdf>
He probably designed that without Spice.
The first IC opamp I tried was made by GE. All NPN, with an internal
zener in the level-shift part. It was amazingly noisy.
The "natural" CMRR and PSRR of a diff pair stinks without active loads,
at least on one of the rails; Thompson had to use tricks to get around
that to keep the output sitting at zero when the inputs were equal
I designed some little baby-board opamps, all TO-92 transistors and
folded-over axial parts. By selecting some resistors we got sub 1 mV
offset and under 1 uV/degC, but it was tedious.
I still have some Philbrick opamps that I found at a flea market.
https://www.dropbox.com/scl/fi/tujdcjpvv7m4b2yo8w751/Philbricks.jpg?rlkey=19ivv2tgqmqiy9ci92lgysrz7&raw=1
Are those the radioactive ones?
It's been around an awfully long time and there are far better
alternatives out there. But is there still a case for using them in
certain niche applications in 2024?
On Mon, 4 Nov 2024 10:49:55 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Jan Panteltje <alien@comet.invalid> wrote:
[...]
I still have a 747 in a box somewhere.
How could you loose anything that size?
I visited a guy in repair facility near the local airport. He said
"Let me show you my repair shop." It had a somewhat disassembled 747
inside with room to spare.
They have a setup for testing jet engines at full power too.
We provided him some electronics for testing APUs, which are prtetty
dinky gadgets.
In the life of an airplane, more is spent on maintanance than the
plane cost. So the maintanance is an interesting market.
On Mon, 04 Nov 2024 07:27:56 -0800, john larkin <JL@gct.com> wrote:
On Mon, 4 Nov 2024 10:49:55 +0000, liz@poppyrecords.invalid.invalid
(Liz Tuddenham) wrote:
Jan Panteltje <alien@comet.invalid> wrote:
[...]
I still have a 747 in a box somewhere.
How could you loose anything that size?
I visited a guy in repair facility near the local airport. He said
"Let me show you my repair shop." It had a somewhat disassembled 747
inside with room to spare.
They have a setup for testing jet engines at full power too.
We provided him some electronics for testing APUs, which are prtetty
dinky gadgets.
They are, aren't they? Amazing things to watch close up spinning into
life and revving up to god only knows what sort of RPM.
I have a friend who's seriously into radio-controlled model aircraft.
They're about 5 feet long and are powered by actual jet engines! Still
can't get my head around that.
In the life of an airplane, more is spent on maintanance than the
plane cost. So the maintenance is an interesting market.
Back when I was interested in model aircraft as a kid there were model
jet engines, but they were pulse jets, of the sort used to power the V1 missiles at the end of WW2.
On 2024-11-06, Bill Sloman <bill.sloman@ieee.org> wrote:
Back when I was interested in model aircraft as a kid there were model
jet engines, but they were pulse jets, of the sort used to power the V1
missiles at the end of WW2.
Real model jet turbines are available for some time now - some in quite
small form factor. I talked to one guy at a flight show who had one of
these in a small EPP foam model converted as a jet trainer:
https://lambert-modellturbinen-onlineshop.de/
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