Gentlemen,
I've decided a nice project would be to build a curve tracer which
would (because I'm a vintage nut) use a CRT display of an
oscilloscope. From time to time I have these Big Ideas and it could >conceivably become the latest in a long line of my unfinished
projects.
Which curves would be essential to include for a decent, functional
design? I know what the obvious ones are; just wondering if there are
any more obscure ones which would be advantageous to plot. Finally,
are there any additions one could make to a classic curve tracer's >functionality which were omitted from the early designs (modulation
feature at 1Mhz,100Mhz or whatever) for example?
CD.
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]>
wrote:
Gentlemen,
I've decided a nice project would be to build a curve tracer which
would (because I'm a vintage nut) use a CRT display of an
oscilloscope. From time to time I have these Big Ideas and it could >>conceivably become the latest in a long line of my unfinished
projects.
Which curves would be essential to include for a decent, functional
design? I know what the obvious ones are; just wondering if there are
any more obscure ones which would be advantageous to plot. Finally,
are there any additions one could make to a classic curve tracer's >>functionality which were omitted from the early designs (modulation
feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and
forgets instantly. A digital scope would fix that. A curve tracer
should be able to trigger the scope and do short single-shot events.
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]>
wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>wrote:
Gentlemen,
I've decided a nice project would be to build a curve tracer which
would (because I'm a vintage nut) use a CRT display of an
oscilloscope. From time to time I have these Big Ideas and it could >>>conceivably become the latest in a long line of my unfinished
projects.
Which curves would be essential to include for a decent, functional >>>design? I know what the obvious ones are; just wondering if there are
any more obscure ones which would be advantageous to plot. Finally,
are there any additions one could make to a classic curve tracer's >>>functionality which were omitted from the early designs (modulation >>>feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>forgets instantly. A digital scope would fix that. A curve tracer
should be able to trigger the scope and do short single-shot events.
DSOs have their own disadvantages for this sort of thing.
These people make this little thing with a CT function, but it needs a >computer screen and is only capable of applying up to 10V! The stupid
fucks have only used a single AAA battery for its power source. Can
you believe that? I suspect there'll be a revised model along in due
course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]>
wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>wrote:
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>would (because I'm a vintage nut) use a CRT display of an
oscilloscope. From time to time I have these Big Ideas and it could >>>>conceivably become the latest in a long line of my unfinished
projects.
Which curves would be essential to include for a decent, functional >>>>design? I know what the obvious ones are; just wondering if there are >>>>any more obscure ones which would be advantageous to plot. Finally,
are there any additions one could make to a classic curve tracer's >>>>functionality which were omitted from the early designs (modulation >>>>feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>forgets instantly. A digital scope would fix that. A curve tracer
should be able to trigger the scope and do short single-shot events.
DSOs have their own disadvantages for this sort of thing.
These people make this little thing with a CT function, but it needs a >>computer screen and is only capable of applying up to 10V! The stupid
fucks have only used a single AAA battery for its power source. Can
you believe that? I suspect there'll be a revised model along in due
course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond
or less, so a curve tracer can have some tiny power supplies and a few
big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4
isolated channels, which is handy snooping drain currents and such.
On 2025-02-04, john larkin <[email protected]> wrote:
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]>
wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>>wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>>wrote:
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>>would (because I'm a vintage nut) use a CRT display of an >>>>>oscilloscope. From time to time I have these Big Ideas and it could >>>>>conceivably become the latest in a long line of my unfinished >>>>>projects.
Which curves would be essential to include for a decent, functional >>>>>design? I know what the obvious ones are; just wondering if there are >>>>>any more obscure ones which would be advantageous to plot. Finally, >>>>>are there any additions one could make to a classic curve tracer's >>>>>functionality which were omitted from the early designs (modulation >>>>>feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>>destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>>forgets instantly. A digital scope would fix that. A curve tracer >>>>should be able to trigger the scope and do short single-shot events.
DSOs have their own disadvantages for this sort of thing.
These people make this little thing with a CT function, but it needs a >>>computer screen and is only capable of applying up to 10V! The stupid >>>fucks have only used a single AAA battery for its power source. Can
you believe that? I suspect there'll be a revised model along in due >>>course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond
or less, so a curve tracer can have some tiny power supplies and a few
big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4
isolated channels, which is handy snooping drain currents and such.
(crossing threads... )
I've sometimes wondered if a gadget could be made that analyses a component >and spits out a spice model for it.
Maybe if fed with multiple samples of the same component it could average
out the parameters.
On Wed, 5 Feb 2025 08:27:01 -0000 (UTC), Ian ><${send-direct-email-to-news1021-at-jusme-dot-com-if-you-must}@jusme.com> >wrote:
On 2025-02-04, john larkin <[email protected]> wrote:
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]>
wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>>>wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>>>wrote:
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>>>would (because I'm a vintage nut) use a CRT display of an >>>>>>oscilloscope. From time to time I have these Big Ideas and it could >>>>>>conceivably become the latest in a long line of my unfinished >>>>>>projects.
Which curves would be essential to include for a decent, functional >>>>>>design? I know what the obvious ones are; just wondering if there are >>>>>>any more obscure ones which would be advantageous to plot. Finally, >>>>>>are there any additions one could make to a classic curve tracer's >>>>>>functionality which were omitted from the early designs (modulation >>>>>>feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>>>destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>>>forgets instantly. A digital scope would fix that. A curve tracer >>>>>should be able to trigger the scope and do short single-shot events.
DSOs have their own disadvantages for this sort of thing.
These people make this little thing with a CT function, but it needs a >>>>computer screen and is only capable of applying up to 10V! The stupid >>>>fucks have only used a single AAA battery for its power source. Can
you believe that? I suspect there'll be a revised model along in due >>>>course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond
or less, so a curve tracer can have some tiny power supplies and a few
big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4
isolated channels, which is handy snooping drain currents and such.
(crossing threads... )
I've sometimes wondered if a gadget could be made that analyses a component >>and spits out a spice model for it.
Maybe if fed with multiple samples of the same component it could average >>out the parameters.
That is actually a really interesting idea if it could be implemented. >However it goes beyond my pay grade so I'll have to defer to those
more knowledgeable about generating models for an answer to that.
John, that was the other aspect I meant to say could use updating:
instead of having rows of switches and level controls, would it not be
better to let a Pi or an Arduino do all the heavy lifting. The
programming for such a straightforward task to automate things would
be pretty elementary and make the use of the device so much faster.
Oh - one other feature: a 'subtract' function to analyze a batch of >'identical' devices to quickly select matched-pairs. Again that would
require some computerization.
On Wed, 05 Feb 2025 15:33:11 +0000, Cursitor Doom <[email protected]>
wrote:
On Wed, 5 Feb 2025 08:27:01 -0000 (UTC), Ian
<${send-direct-email-to-news1021-at-jusme-dot-com-if-you-must}@jusme.com>
wrote:
On 2025-02-04, john larkin <[email protected]> wrote:
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]>
wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>>>> wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>>>> wrote:DSOs have their own disadvantages for this sort of thing.
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>>>> would (because I'm a vintage nut) use a CRT display of an
oscilloscope. From time to time I have these Big Ideas and it could >>>>>>> conceivably become the latest in a long line of my unfinished
projects.
Which curves would be essential to include for a decent, functional >>>>>>> design? I know what the obvious ones are; just wondering if there are >>>>>>> any more obscure ones which would be advantageous to plot. Finally, >>>>>>> are there any additions one could make to a classic curve tracer's >>>>>>> functionality which were omitted from the early designs (modulation >>>>>>> feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>>>> destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>>>> forgets instantly. A digital scope would fix that. A curve tracer
should be able to trigger the scope and do short single-shot events. >>>>>
These people make this little thing with a CT function, but it needs a >>>>> computer screen and is only capable of applying up to 10V! The stupid >>>>> fucks have only used a single AAA battery for its power source. Can
you believe that? I suspect there'll be a revised model along in due >>>>> course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond
or less, so a curve tracer can have some tiny power supplies and a few >>>> big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4
isolated channels, which is handy snooping drain currents and such.
(crossing threads... )
I've sometimes wondered if a gadget could be made that analyses a component >>> and spits out a spice model for it.
Maybe if fed with multiple samples of the same component it could average >>> out the parameters.
That is actually a really interesting idea if it could be implemented.
However it goes beyond my pay grade so I'll have to defer to those
more knowledgeable about generating models for an answer to that.
John, that was the other aspect I meant to say could use updating:
instead of having rows of switches and level controls, would it not be
better to let a Pi or an Arduino do all the heavy lifting. The
programming for such a straightforward task to automate things would
be pretty elementary and make the use of the device so much faster.
Oh - one other feature: a 'subtract' function to analyze a batch of
'identical' devices to quickly select matched-pairs. Again that would
require some computerization.
Fun, but hardly anyone needs matched pairs these days, with cheap
opamps having microvolt offsets and nanovolt drift.
On Wed, 05 Feb 2025 15:33:11 +0000, Cursitor Doom <[email protected]>
wrote:
On Wed, 5 Feb 2025 08:27:01 -0000 (UTC), Ian >><${send-direct-email-to-news1021-at-jusme-dot-com-if-you-must}@jusme.com> >>wrote:
On 2025-02-04, john larkin <[email protected]> wrote:
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]>
wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>>>>wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>>>>wrote:DSOs have their own disadvantages for this sort of thing.
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>>>>would (because I'm a vintage nut) use a CRT display of an >>>>>>>oscilloscope. From time to time I have these Big Ideas and it could >>>>>>>conceivably become the latest in a long line of my unfinished >>>>>>>projects.
Which curves would be essential to include for a decent, functional >>>>>>>design? I know what the obvious ones are; just wondering if there are >>>>>>>any more obscure ones which would be advantageous to plot. Finally, >>>>>>>are there any additions one could make to a classic curve tracer's >>>>>>>functionality which were omitted from the early designs (modulation >>>>>>>feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>>>>destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>>>>forgets instantly. A digital scope would fix that. A curve tracer >>>>>>should be able to trigger the scope and do short single-shot events. >>>>>
These people make this little thing with a CT function, but it needs a >>>>>computer screen and is only capable of applying up to 10V! The stupid >>>>>fucks have only used a single AAA battery for its power source. Can >>>>>you believe that? I suspect there'll be a revised model along in due >>>>>course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond
or less, so a curve tracer can have some tiny power supplies and a few >>>> big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4
isolated channels, which is handy snooping drain currents and such.
(crossing threads... )
I've sometimes wondered if a gadget could be made that analyses a component >>>and spits out a spice model for it.
Maybe if fed with multiple samples of the same component it could average >>>out the parameters.
That is actually a really interesting idea if it could be implemented. >>However it goes beyond my pay grade so I'll have to defer to those
more knowledgeable about generating models for an answer to that.
John, that was the other aspect I meant to say could use updating:
instead of having rows of switches and level controls, would it not be >>better to let a Pi or an Arduino do all the heavy lifting. The
programming for such a straightforward task to automate things would
be pretty elementary and make the use of the device so much faster.
Oh - one other feature: a 'subtract' function to analyze a batch of >>'identical' devices to quickly select matched-pairs. Again that would >>require some computerization.
Fun, but hardly anyone needs matched pairs these days, with cheap
opamps having microvolt offsets and nanovolt drift.
On Wed, 05 Feb 2025 08:18:49 -0800, john larkin <[email protected]> wrote:
On Wed, 05 Feb 2025 15:33:11 +0000, Cursitor Doom <[email protected]> >>wrote:
On Wed, 5 Feb 2025 08:27:01 -0000 (UTC), Ian >>><${send-direct-email-to-news1021-at-jusme-dot-com-if-you-must}@jusme.com> >>>wrote:
On 2025-02-04, john larkin <[email protected]> wrote:
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]> >>>>> wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>>>>>wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>>>>>wrote:DSOs have their own disadvantages for this sort of thing.
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>>>>>would (because I'm a vintage nut) use a CRT display of an >>>>>>>>oscilloscope. From time to time I have these Big Ideas and it could >>>>>>>>conceivably become the latest in a long line of my unfinished >>>>>>>>projects.
Which curves would be essential to include for a decent, functional >>>>>>>>design? I know what the obvious ones are; just wondering if there are >>>>>>>>any more obscure ones which would be advantageous to plot. Finally, >>>>>>>>are there any additions one could make to a classic curve tracer's >>>>>>>>functionality which were omitted from the early designs (modulation >>>>>>>>feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>>>>>destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>>>>>forgets instantly. A digital scope would fix that. A curve tracer >>>>>>>should be able to trigger the scope and do short single-shot events. >>>>>>
These people make this little thing with a CT function, but it needs a >>>>>>computer screen and is only capable of applying up to 10V! The stupid >>>>>>fucks have only used a single AAA battery for its power source. Can >>>>>>you believe that? I suspect there'll be a revised model along in due >>>>>>course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond >>>>> or less, so a curve tracer can have some tiny power supplies and a few >>>>> big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4 >>>>> isolated channels, which is handy snooping drain currents and such.
(crossing threads... )
I've sometimes wondered if a gadget could be made that analyses a component >>>>and spits out a spice model for it.
Maybe if fed with multiple samples of the same component it could average >>>>out the parameters.
That is actually a really interesting idea if it could be implemented. >>>However it goes beyond my pay grade so I'll have to defer to those
more knowledgeable about generating models for an answer to that.
John, that was the other aspect I meant to say could use updating: >>>instead of having rows of switches and level controls, would it not be >>>better to let a Pi or an Arduino do all the heavy lifting. The >>>programming for such a straightforward task to automate things would
be pretty elementary and make the use of the device so much faster.
Oh - one other feature: a 'subtract' function to analyze a batch of >>>'identical' devices to quickly select matched-pairs. Again that would >>>require some computerization.
Fun, but hardly anyone needs matched pairs these days, with cheap
opamps having microvolt offsets and nanovolt drift.
I had power output devices for RF and/or audio in mind, John. Also, in
my particular interest of vintage equipment repair, one frequently
encounters double transistors: two BJTs in a single package which are
matched and thermally bonded by their mutual encapsulation. These are >unobtainium nowadays,, so subbing in two discrete devices with the
same characteristics bonded together is the only viable alternative.
On Wed, 05 Feb 2025 23:44:30 +0000, Cursitor Doom <[email protected]>
wrote:
On Wed, 05 Feb 2025 08:18:49 -0800, john larkin <[email protected]> wrote:
On Wed, 05 Feb 2025 15:33:11 +0000, Cursitor Doom <[email protected]>
wrote:
On Wed, 5 Feb 2025 08:27:01 -0000 (UTC), Ian
<${send-direct-email-to-news1021-at-jusme-dot-com-if-you-must}@jusme.com> >>>> wrote:
On 2025-02-04, john larkin <[email protected]> wrote:
On Tue, 04 Feb 2025 23:03:34 +0000, Cursitor Doom <[email protected]> >>>>>> wrote:
On Tue, 04 Feb 2025 10:19:40 -0800, john larkin <[email protected]> >>>>>>> wrote:
On Tue, 04 Feb 2025 16:51:22 +0000, Cursitor Doom <[email protected]> >>>>>>>> wrote:DSOs have their own disadvantages for this sort of thing.
Gentlemen,
I've decided a nice project would be to build a curve tracer which >>>>>>>>> would (because I'm a vintage nut) use a CRT display of an
oscilloscope. From time to time I have these Big Ideas and it could >>>>>>>>> conceivably become the latest in a long line of my unfinished >>>>>>>>> projects.
Which curves would be essential to include for a decent, functional >>>>>>>>> design? I know what the obvious ones are; just wondering if there are >>>>>>>>> any more obscure ones which would be advantageous to plot. Finally, >>>>>>>>> are there any additions one could make to a classic curve tracer's >>>>>>>>> functionality which were omitted from the early designs (modulation >>>>>>>>> feature at 1Mhz,100Mhz or whatever) for example?
CD.
I'd like to see pulsed avalanche behavior of mosfets, preferably to >>>>>>>> destruction.
C-V curves would be great too.
Stuff that's not on the data sheet.
The thing about an analog CRT scope is that it isn't quantitative and >>>>>>>> forgets instantly. A digital scope would fix that. A curve tracer >>>>>>>> should be able to trigger the scope and do short single-shot events. >>>>>>>
These people make this little thing with a CT function, but it needs a >>>>>>> computer screen and is only capable of applying up to 10V! The stupid >>>>>>> fucks have only used a single AAA battery for its power source. Can >>>>>>> you believe that? I suspect there'll be a revised model along in due >>>>>>> course which has a far better voltage range.
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html
Given a digital scope, most measurements can be done in a millisecond >>>>>> or less, so a curve tracer can have some tiny power supplies and a few >>>>>> big caps.
People don't use bipolar transistors much any more, so one could
emphasize tracing mosfets and GaN fets and SiC parts.
When I need to characterize a part, I hack up a setup with power
supplies and pulse generators and stuff. We have a Tek scope with 4 >>>>>> isolated channels, which is handy snooping drain currents and such. >>>>>>
(crossing threads... )
I've sometimes wondered if a gadget could be made that analyses a component
and spits out a spice model for it.
Maybe if fed with multiple samples of the same component it could average >>>>> out the parameters.
That is actually a really interesting idea if it could be implemented. >>>> However it goes beyond my pay grade so I'll have to defer to those
more knowledgeable about generating models for an answer to that.
John, that was the other aspect I meant to say could use updating:
instead of having rows of switches and level controls, would it not be >>>> better to let a Pi or an Arduino do all the heavy lifting. The
programming for such a straightforward task to automate things would
be pretty elementary and make the use of the device so much faster.
Oh - one other feature: a 'subtract' function to analyze a batch of
'identical' devices to quickly select matched-pairs. Again that would
require some computerization.
Fun, but hardly anyone needs matched pairs these days, with cheap
opamps having microvolt offsets and nanovolt drift.
I had power output devices for RF and/or audio in mind, John. Also, in
my particular interest of vintage equipment repair, one frequently
encounters double transistors: two BJTs in a single package which are
matched and thermally bonded by their mutual encapsulation. These are
unobtainium nowadays,, so subbing in two discrete devices with the
same characteristics bonded together is the only viable alternative.
There are lots of dual transistors around these days, but they are
most always two die in one package, off the same wafer but otherwise unmatched.
Their thermals are terrible:
https://www.dropbox.com/scl/fi/sa0oqspnuulwxyjohiu20/UPA800_80mW_one-side.jpg?rlkey=p6m43rzq2nvx5we5hlptnt1qk&raw=1
Since the two transistors in a current mirror rarely dissipate the
same power, such a dual transistor makes a rotten mirror. They are OK
in a small-signal diffamp where both sides have about the same small
power dissipation.
There were some real monolithic duals, complex interdigitated
patterns, not galvanically isolated, very expensive.
There are lots of dual transistors around these days, but they are
most always two die in one package, off the same wafer but otherwise unmatched.
There were some real monolithic duals, complex interdigitated
patterns, not galvanically isolated, very expensive.
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate
chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no
longer be matched if the dissipation is not the same between them. You
could cascode a current mirror to fix that, but if you are trying to
make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different >currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called >"substrate" or a note saying one of the pins is the substrate, and there
will be a spec pointing out that the voltage between the two devices
must be kept below some lowish value.
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate
chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no
longer be matched if the dissipation is not the same between them. You
could cascode a current mirror to fix that, but if you are trying to
make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different
currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called
"substrate" or a note saying one of the pins is the substrate, and there
will be a spec pointing out that the voltage between the two devices
must be kept below some lowish value.
They are two similar chips, not monolithic. Thermals will be awful.
On 6/02/2025 1:10 pm, john larkin wrote:
There were some real monolithic duals, complex interdigitated
patterns, not galvanically isolated, very expensive.
The CA3046 / LM3046 were cheap until they stopped selling them.
Fortunately I have several tubes of them left.
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate
chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no
longer be matched if the dissipation is not the same between them. You
could cascode a current mirror to fix that, but if you are trying to
make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different
currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called
"substrate" or a note saying one of the pins is the substrate, and there >>> will be a spec pointing out that the voltage between the two devices
must be kept below some lowish value.
You would know if they were monolithic if they did have a substrate pin.
The fact that they haven't got one isn't proof that they aren't
monolithic. A stronger argument is that they haven't put any limits on device-to-device voltages.
My reason for thinking that they were monolithic was the 2mV worst case
and the 1mVB typical difference in Vbe at 2mA.
Monolithic does seem to offer the cheapest route to get that.
They are two similar chips, not monolithic. Thermals will be awful.
Prove it.
They may be two separate close-to-identical chips. There isn't room in
the package to mount them far apart, and the chip to chip thermal
resistance can't be large, and has to be much smaller than the package
to ambient thermal resistance, which is 328C/Watt.
Thermals won't be awful. Somebody who doesn't know about Wilson current mirrors isn't going to be a particularly reliable source of information
about that kind of subject.
Interdigitated monolithic is hard to beat for thermal matching but side-by-side devices on the same subtrate aren't going to be any better
than devices on separate substrates if the substrates are mounted back-to-back.
--
Bill Sloman, Sydney
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate
chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no
longer be matched if the dissipation is not the same between them. You >>>> could cascode a current mirror to fix that, but if you are trying to
make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different
currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called >>>> "substrate" or a note saying one of the pins is the substrate, and there >>>> will be a spec pointing out that the voltage between the two devices
must be kept below some lowish value.
You would know if they were monolithic if they did have a substrate pin.
The fact that they haven't got one isn't proof that they aren't
monolithic. A stronger argument is that they haven't put any limits on
device-to-device voltages.
My reason for thinking that they were monolithic was the 2mV worst case
and the 1mVB typical difference in Vbe at 2mA.
Monolithic does seem to offer the cheapest route to get that.
They are two similar chips, not monolithic. Thermals will be awful.
Prove it.
They may be two separate close-to-identical chips. There isn't room in
the package to mount them far apart, and the chip to chip thermal
resistance can't be large, and has to be much smaller than the package
to ambient thermal resistance, which is 328C/Watt.
Thermals won't be awful. Somebody who doesn't know about Wilson current
mirrors isn't going to be a particularly reliable source of information
about that kind of subject.
Interdigitated monolithic is hard to beat for thermal matching but
side-by-side devices on the same subtrate aren't going to be any better
than devices on separate substrates if the substrates are mounted
back-to-back.
--
Bill Sloman, Sydney
I seem to remember someone here has an xray machine which could answer the question?
piglet <[email protected]> wrote:
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate >>>>> chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no >>>>> longer be matched if the dissipation is not the same between them. You >>>>> could cascode a current mirror to fix that, but if you are trying to >>>>> make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different >>>>> currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called >>>>> "substrate" or a note saying one of the pins is the substrate, and there >>>>> will be a spec pointing out that the voltage between the two devices >>>>> must be kept below some lowish value.
You would know if they were monolithic if they did have a substrate pin. >>>
The fact that they haven't got one isn't proof that they aren't
monolithic. A stronger argument is that they haven't put any limits on
device-to-device voltages.
My reason for thinking that they were monolithic was the 2mV worst case
and the 1mVB typical difference in Vbe at 2mA.
Monolithic does seem to offer the cheapest route to get that.
They are two similar chips, not monolithic. Thermals will be awful.
Prove it.
They may be two separate close-to-identical chips. There isn't room in
the package to mount them far apart, and the chip to chip thermal
resistance can't be large, and has to be much smaller than the package
to ambient thermal resistance, which is 328C/Watt.
Thermals won't be awful. Somebody who doesn't know about Wilson current
mirrors isn't going to be a particularly reliable source of information
about that kind of subject.
Interdigitated monolithic is hard to beat for thermal matching but
side-by-side devices on the same subtrate aren't going to be any better
than devices on separate substrates if the substrates are mounted
back-to-back.
I seem to remember someone here has an xray machine which could answer the >> question?
It’s a FAQ that we’ve gone through many times, including my doing a bit of
math on the datasheet for the BCV61 current mirror that used its thermal runaway spec to estimate the die-to-die thermal resistance.
Turns out to be about the same as the die-to-ambient, 300-500 K/W.
They really aren’t monolithic.
piglet <[email protected]> wrote:
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate >>>>> chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no >>>>> longer be matched if the dissipation is not the same between them. You >>>>> could cascode a current mirror to fix that, but if you are trying to >>>>> make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different >>>>> currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called >>>>> "substrate" or a note saying one of the pins is the substrate, and there >>>>> will be a spec pointing out that the voltage between the two devices >>>>> must be kept below some lowish value.
You would know if they were monolithic if they did have a substrate pin. >>>
The fact that they haven't got one isn't proof that they aren't
monolithic. A stronger argument is that they haven't put any limits on
device-to-device voltages.
My reason for thinking that they were monolithic was the 2mV worst case
and the 1mVB typical difference in Vbe at 2mA.
Monolithic does seem to offer the cheapest route to get that.
They are two similar chips, not monolithic. Thermals will be awful.
Prove it.
They may be two separate close-to-identical chips. There isn't room in
the package to mount them far apart, and the chip to chip thermal
resistance can't be large, and has to be much smaller than the package
to ambient thermal resistance, which is 328C/Watt.
Thermals won't be awful. Somebody who doesn't know about Wilson current
mirrors isn't going to be a particularly reliable source of information
about that kind of subject.
Interdigitated monolithic is hard to beat for thermal matching but
side-by-side devices on the same subtrate aren't going to be any better
than devices on separate substrates if the substrates are mounted
back-to-back.
--
Bill Sloman, Sydney
I seem to remember someone here has an xray machine which could answer the >> question?
It�s a FAQ that we�ve gone through many times, including my doing a bit of >math on the datasheet for the BCV61 current mirror that used its thermal >runaway spec to estimate the die-to-die thermal resistance.
Turns out to be about the same as the die-to-ambient, 300-500 K/W.
They really aren�t monolithic.
Cheers
Phil Hobbs
There
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
What makes you think those are monolithic? I think they are separate
chips, but measured to have similar parameters, like the BCM846BS.
The thermal coupling between the chips will be poor, so they will no
longer be matched if the dissipation is not the same between them. You >>>> could cascode a current mirror to fix that, but if you are trying to
make an exponentiator (as used in analogue synth VCOs) then you are
stuffed, because you need to operate the two transistors at different
currents, that being the whole point of the circuit.
You will know if they are monolithic because it will have a pin called >>>> "substrate" or a note saying one of the pins is the substrate, and there >>>> will be a spec pointing out that the voltage between the two devices
must be kept below some lowish value.
You would know if they were monolithic if they did have a substrate pin.
The fact that they haven't got one isn't proof that they aren't
monolithic. A stronger argument is that they haven't put any limits on
device-to-device voltages.
My reason for thinking that they were monolithic was the 2mV worst case
and the 1mVB typical difference in Vbe at 2mA.
Monolithic does seem to offer the cheapest route to get that.
They are two similar chips, not monolithic. Thermals will be awful.
Prove it.
They may be two separate close-to-identical chips. There isn't room in
the package to mount them far apart, and the chip to chip thermal
resistance can't be large, and has to be much smaller than the package
to ambient thermal resistance, which is 328C/Watt.
Thermals won't be awful. Somebody who doesn't know about Wilson current
mirrors isn't going to be a particularly reliable source of information
about that kind of subject.
Interdigitated monolithic is hard to beat for thermal matching but
side-by-side devices on the same subtrate aren't going to be any better
than devices on separate substrates if the substrates are mounted
back-to-back.
--
Bill Sloman, Sydney
I seem to remember someone here has an xray machine which could answer the >question?
On Fri, 7 Feb 2025 14:18:48 -0000 (UTC), Phil Hobbs><[email protected]> wrote:
to fix that, but if you arepiglet <[email protected]> wrote:
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
On-Semi makes two monolithic duals, the NST45010 and the
NST45011
https://www.onsemi.com/pdf/datasheet/nst45010mw6-d.pdf
https://www.onsemi.com/download/data-sheet/pdf/nst45011mw6-d.pdf
Whatmakes you think those are monolithic? I think they are separatechips, but measured to have similar parameters, like the
BCM846BS.
The thermal coupling between the chips will be poor, so
they will no longer be matched if the dissipation is not
the same betweenthem. You>>>>>> could cascode a current mirror
is thetrying to make an exponentiator (as used in analogue synth
VCOs) then you are stuffed, because you need to operate
the two transistors at different currents, that being the
whole point of the circuit.
You will know if they are monolithic because it will have
a pincalled>>>>>> "substrate" or a note saying one of the pins
voltage between thesubstrate,and there>>>>>> will be a spec pointing out that the
answer the>>> question?two devices must be kept below some lowish value.
You would know if they were monolithic if they did have a
substratepin.>>>>
The fact that they haven't got one isn't proof that they aren't
monolithic. A stronger argument is that they haven't put any
limits on device-to-device voltages.
My reason for thinking that they were monolithic was the 2mV
worst case and the 1mVB typical difference in Vbe at 2mA.
Monolithic does seem to offer the cheapest route to get that.
They are two similar chips, not monolithic. Thermals will be
awful.
Prove it.
They may be two separate close-to-identical chips. There isn't
room in the package to mount them far apart, and the chip to
chip thermal resistance can't be large, and has to be much
smaller than the package to ambient thermal resistance, which
is 328C/Watt.
Thermals won't be awful. Somebody who doesn't know about
Wilson current mirrors isn't going to be a particularly
reliable source of information about that kind of subject.
Interdigitated monolithic is hard to beat for thermal matching
but side-by-side devices on the same subtrate aren't going to
be any better than devices on separate substrates if the
substrates are mounted back-to-back.
-- Bill Sloman, Sydney
I seem to remember someone here has an xray machine which could
mirror that used its
It\u2019s a FAQ that we\u2019ve gone through many times, including
mydoing a bit of>> math on the datasheet for the BCV61 current
The "Dr Hobbs" business is strictly reserved for opposing counsel. ;)thermal runaway spec to estimate the die-to-die thermal
resistance.
Turns out to be about the same as the die-to-ambient, 300-500 K/W.
They really aren\u2019t monolithic.
Cheers
Phil Hobbs
Right. Those dual-chip things are not much better thermally then two
SOT-23s mounted close on a board.
I make current mirrors now and then, with an opamp and a mosfet. Or,
sometimes, just an opamp. That's way more accurate than the
transistor versions.
Hey, Dr Hobbs, what is the attraction that PhDs seem to have for
current mirrors?
On Fri, 7 Feb 2025 14:18:48 -0000 (UTC), Phil Hobbs <[email protected]> wrote:
piglet <[email protected]> wrote:
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
I make current mirrors now and then, with an opamp and a mosfet. Or, sometimes, just an opamp. That's way more accurate than the transistor versions.
Hey, Dr Hobbs, what is the attraction that PhDs seem to have for
current mirrors?
On 6/02/2025 11:01 pm, Chris Jones wrote:
On 6/02/2025 1:10 pm, john larkin wrote:
There were some real monolithic duals, complex interdigitated
patterns, not galvanically isolated, very expensive.
The CA3046 / LM3046 were cheap until they stopped selling them.
Fortunately I have several tubes of them left.
Renesas Still seems to make the much faster HFA3096
https://www.renesas.com/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet
https://au.element14.com/renesas/hfa3096bz/ic-transistor-array-ultra-h-freq/dp/1562039
Mouser seems to have some of them too.
On Fri, 7 Feb 2025 14:18:48 -0000 (UTC), Phil Hobbs <[email protected]> wrote:
piglet <[email protected]> wrote:
Bill Sloman <[email protected]> wrote:
On 7/02/2025 8:18 am, john larkin wrote:
On Thu, 6 Feb 2025 23:11:58 +1100, Chris Jones
<[email protected]> wrote:
On 6/02/2025 2:45 pm, Bill Sloman wrote:
Right. Those dual-chip things are not much better thermally then two
SOT-23s mounted close on a board.
I make current mirrors now and then, with an opamp and a mosfet. Or, sometimes, just an opamp. That's way more accurate than the transistor versions.
Hey, Dr Hobbs, what is the attraction that Ph.D.s seem to have for
current mirrors?
On 7/02/2025 11:27 pm, Bill Sloman wrote:
On 6/02/2025 11:01 pm, Chris Jones wrote:
On 6/02/2025 1:10 pm, john larkin wrote:
There were some real monolithic duals, complex interdigitated
patterns, not galvanically isolated, very expensive.
The CA3046 / LM3046 were cheap until they stopped selling them.
Fortunately I have several tubes of them left.
Renesas Still seems to make the much faster HFA3096
https://www.renesas.com/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet
https://au.element14.com/renesas/hfa3096bz/ic-transistor-array-ultra-h-freq/dp/1562039
Mouser seems to have some of them too.
I know about them and I'm glad they still make them, but they are not
cheap and are single-source.
Anyone know anything about this company?
https://www.alfarzpp.lv/eng/sc/semiconductor.php
On Sat, 8 Feb 2025 21:44:20 +1100, Chris Jones
<[email protected]> wrote:
On 7/02/2025 11:27 pm, Bill Sloman wrote:
On 6/02/2025 11:01 pm, Chris Jones wrote:
On 6/02/2025 1:10 pm, john larkin wrote:
There were some real monolithic duals, complex interdigitated
patterns, not galvanically isolated, very expensive.
The CA3046 / LM3046 were cheap until they stopped selling them.
Fortunately I have several tubes of them left.
Renesas Still seems to make the much faster HFA3096
https://www.renesas.com/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet
https://au.element14.com/renesas/hfa3096bz/ic-transistor-array-ultra-h-freq/dp/1562039
Mouser seems to have some of them too.
I know about them and I'm glad they still make them, but they are not
cheap and are single-source.
Anyone know anything about this company?
https://www.alfarzpp.lv/eng/sc/semiconductor.php
Interesting, in Latvia. They are agnostic, or maybe random, about
using commas or decimal points as digit separators.
Kinda grim on Street View, typical Russia/former satellite sort of
look.
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