Author Topic: So what do you do when you need a modern transistor curve tracer?  (Read 10882 times)

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Offline switchabl

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #25 on: February 19, 2023, 10:51:35 pm »
There are current model curve tracers out there but it depends what kind of voltages and currents you want to test the DUT at, as well as the volume of parts you want to test.

That's a bold statement.  Can you name even one that is a standalone unit, not an SMU?

Off the top of my head: Keysight B1500A, Keithley 4200A-SCS, several Iwatsu models. Yes they do a lot more than just I/V curves these days and they are not cheap. But neither was a Tek 370.
 

Offline alm

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #26 on: February 19, 2023, 11:00:06 pm »
That's a bold statement.  Can you name even one that is a standalone unit, not an SMU?  (I don't think the above mentioned Keysight B1500A counts, since it's an SMU system in a box
Why is a system consisting of a number of SMUs in a box that can trace curves not a curve tracer? The traditional Tek 576 etc also had voltage/current sources and voltage / ammeters (on the CRT).

and I also think OP doesn't want to spend $86K+.)
Unfortunately the OP was last active in July, 2022, so we'll probably never know. This company claims to sell the Keithley equivalent for less than half ;). But if you want something that a cal lab will certify, then I think it's either this or a stack of SMUs, and I'm not sure the latter will be all that much cheaper, especially if you factor in software (buying or developing it yourself).

Offline edavid

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #27 on: February 20, 2023, 12:18:29 am »
Why is a system consisting of a number of SMUs in a box that can trace curves not a curve tracer? The traditional Tek 576 etc also had voltage/current sources and voltage / ammeters (on the CRT).
I don't have a good answer, except maybe the time required to set up a simple measurement?

Quote
Unfortunately the OP was last active in July, 2022, so we'll probably never know.
Whoops!

Quote
This company claims to sell the Keithley equivalent for less than half ;).
That's $34K for just the mainframe, so it does add up once you add the SMUs :)
 

Offline alm

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #28 on: February 20, 2023, 12:47:23 am »
I don't have a good answer, except maybe the time required to set up a simple measurement?
Well, my hobby budget is also slightly below the $80k mark, so I haven't used these instruments, but I'd expect them to ship with ready made templates for easy IV tracing, BJT tracing, etc. Even the old HP 4145A/B and 4155A could do this fairly easily, although you would have to tell them which channels to use and over what range to sweep. Once set up you could save these settings to disk.

I'd even expect the modern Keithley (and probably also Keysight) SMUs to easily do this with their software. Wasn't one of the big selling points for the Keithley 2450/2460 how easily they could be scripted, and how a script could control multiple instruments? But I'm sure they found a way to charge a crazy amount of money for this somehow.

That's $34K for just the mainframe, so it does add up once you add the SMUs :)
Oops, that is pretty useless on its own indeed...

Offline Whitefoot

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #29 on: February 20, 2023, 02:13:49 am »
There is a Taiwan company named K&H that makes a stand-alone curve tracer.
I don't know anything about it, including price or availability.

https://www.kandh.com.tw/ki-3020d-digitized-semiconductor-curve-tracer-ki-3020d.html
 

Offline David Aurora

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #30 on: February 20, 2023, 01:00:32 pm »
Why would one want to use a curve tracer in 2023?

I use the shit out of mine  :-//

Quality control of crucial components is the main thing for me, but I've also used it to pin down weird problems to fake or intermittent devices when nothing else made sense. I use it for matching components, I use it to analyse things like zener diode curves in design, all kinds of stuff. Lately it's saved me a couple times when I needed oddball transistors that you can't get new from reputable sources and found fakes/duds amongst them. Problems you just can't catch on a multimeter or basic transistor checker like breakdown voltages not meeting spec etc. Without a curve tracer it's a game of suck it and see, with a curve tracer you can analyse a couple from a batch and go "Oh... this would have died in a week"
 

Offline David Aurora

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #31 on: February 20, 2023, 01:11:07 pm »
There are current model curve tracers out there but it depends what kind of voltages and currents you want to test the DUT at, as well as the volume of parts you want to test.

That's a bold statement.  Can you name even one that is a standalone unit, not an SMU?  (I don't think the above mentioned Keysight B1500A counts, since it's an SMU system in a box, and I also think OP doesn't want to spend $86K+.)

A bold statement? Umm... did you even try googling it?

There are everything from these kits https://www.thaikits.com/index.php/measurement-testing-checker/ch-012-transistor-curve-tracer-adapter-xy-oscilloscopes-2-ranges-biasOnline%20Electronic%20Kit%20Store.html to these little handheld ones https://littlebirdelectronics.com.au/products/atlas-dca-pro-advanced-semiconductor-analyser-with-curve-tracing to add ons for other gear like this https://digilent.com/shop/transistor-tester-for-analog-discovery-enables-characteristic-curve-tracing-for-diodes-and-transistors/ to computer based solutions like this https://www.syscompdesign.com/product/ctr-201/ to old style CRT based ones like this https://www.alibaba.com/product-detail/MCP-QT4810A-TRANSISTOR-CURVE-TRACER_287713173.html?spm=a2700.galleryofferlist.normal_offer.d_title.29f14c85RyLOVR

So yeah, I can name even one.
 

Offline timeandfrequency

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #32 on: February 20, 2023, 02:19:06 pm »
Hi,

I don't know if anyone has already mentioned the PEAK Atlas DCA75 Pro which can be connected to a PC via USB to turn it into a curve tracer :
https://printtec.nl/contents/fr/p3905_PEAK-Atlas-DCA75-Pro-Semiconductor-Analyser.html
https://www.peakelec.co.uk/acatalog/dca75-dca-pro-semiconductor-analyser.html

Anyway, should @slow_rider need a more professional gear, maybe asking a TE brooker could fulfill elevated requirements and provide recent stuff.


Why would one want to use a curve tracer in 2023?
Because it's the best TE you can use to understand how electronic conponents actually work. Also very useful for matching parts and perform ageing or partial failure analysis. With a high voltage unit, you can easily check electrolytic caps for leakage current.

I've got access to a marvellous TEK 576 (dated 1970) and often use a basic component tester/semiconductor analyser for repair and troubleshooting purpose. The latter is even more useful than an oscilloscope when reparing gear with severe failure (e.g. SMPS).
If your DUT is dead, there's nothing much to play with a scope, but you can try to identify some fried or out-of-specs parts with a component tester/semiconductor analyser.
« Last Edit: November 13, 2024, 06:45:43 pm by timeandfrequency »
 

Offline baldurn

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #33 on: February 20, 2023, 09:16:24 pm »
Why are there no cheap SMU available? It is just a power supply combined with a DC load so it can both source and sink current?

I wonder if it would be possible to build DIY style.
 

Offline alm

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #34 on: February 20, 2023, 10:35:10 pm »
I'd say a SMU has the following properties:
  • A four-quadrant source, so it supply positive and negative voltages, and source or sink currents (so any voltage polarity combined with any current polarity). This could probably made using a power supply that can sink and source, which I believe includes the latest GW-Instek series, and also older specialty power supplies like the old HP 663xB or 663xx series or Keithley 2302/3/6/8, and a reversing relay.
  • An accurate measurement function (5.5-6.5 digit), which some bench supplies could do an okay job on.
  • Sweep and measure at a pretty high speed, but that's probably not so important for hobby purposes.
  • Numerous decades of current resolution, since testing semiconductors might span from several amps for collector current down to nAs or pAs of leakage current. I'm not so sure how to get this from a cheap power supply, though the Keithley 230x can go pretty low (with some limitations, read the data sheet/manual).

There are some cheap SMUs. The AD ADALM1000 (no relation ;) ) is one example. Performance is not amazing, obviously.

There have been a couple attempts of open hardware SMUs. I think this is by far the furthest along. TiN (xDevs.com) was planning a project at one point, and Youtuber Marco Reps has/had an OSMU project, but I don't either has gotten anywhere near a finished product.
 
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Offline exe

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #35 on: February 20, 2023, 10:42:07 pm »
Why do you need a "trusted calibration"? Semiconductors drift quite a lot with a slight change in temperature (that's why SMU do pulsed current test). Anyway, how important it really is for *you*? Do you really care about every PPM on your curves? I remember if you design a circuit that depends on particular bjt beta then you are doin' it wrong).

As for me, I'm more curious about leakage currents and frequency response.
 

Offline switchabl

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #36 on: February 20, 2023, 11:40:06 pm »
Even if your design depends on device matching (or selection for some parameter) you may not strictly need tracable calibration as long as you can indepently verify the performance of the final product in a tracable manner. But you may want it to be safe and to reduce the chance of rejects.

If, on the other hand, you are manufacturing the BJTs, etc., then you absolutely care. Even more so if you are creating a PDK that others will need to depend on to design complex ASICs. It is true that parameters can change greatly with temperature, and also due to process variation, but that is exactly what you need to characterise. Most people never need to do this, however this is exactly the space that these expensive semiconductor analyzers live in. As for frequency response, they usually come with built-in impedance analysis these days.

Lastly, if you are doing research and are planning on publishing your measurements, IMHO you should care as well. Though I know too well that money may well be tighter in that case...
 

Online Martin72

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #37 on: February 20, 2023, 11:53:06 pm »
Why would one want to use a curve tracer in 2023?

What should have changed that it no longer requires a Curve Tracer ?
I am currently building one based on Arduino.
This is first for learning purposes, because the data is not different from most other tracers.
Because 12Vdc and a few mA are not really suitable to test transistors/FETs for correctness regarding data sheet.

Online chilternview

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #38 on: February 21, 2023, 12:29:48 am »
  • An accurate measurement function (5.5-6.5 digit), which some bench supplies could do an okay job on.

A 3.5 digit measurement capability would be enough, that's a 12 bit ADC and in fact what the HP4145 has (e.g. on +/- 2V range measure with 1mV resolution).

Then if your display has (say) a 0.1mm minimum pixel size, then you could have a screen of up to 40cm across.
 

Offline dobsonr741

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #39 on: February 21, 2023, 03:30:10 pm »
Quote
What should have changed that it no longer requires a Curve Tracer ?

Few changes: analog building blocks are readily available and cheap as integrated ones with very tight tolerances. Like a voltage controlled amplifier, with accurate logarithmic input. Or true RMS converters. 10x better than discrete parts can ever do.

Then in high power you have specialized parts, again with tight tolerances and guaranteed specs. No longer using a vanilla part, then selecting into tighter specs of finding matching pairs like in the 70’s.

And there is the safe operating area, more important than the curve itself. How would you measure that with curve tracer?

In practical terms, if a discrete curve tracer has a meaningful use in today’s engineering than you’d be able to buy one new.

Btw, I’m not discounting semiconductor measurement as a new chip rolls out of the production line or when it’s developed. But that’s not curve tracer, rather a much more complicated semiconductor test equipment, going into measuring dynamic behavior up to the GHz range.

Oh, if you are into retro instrumentation, please go for it. I saw a wonderful curve tracer in the mid eighties, a vacuum tube based transistor curve tracer. It was already vintage 40 years ago.

 

Online chilternview

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #40 on: February 21, 2023, 06:25:17 pm »
There is a big difference between simple curve tracers (think Tek 576, which was designed in the 60's) and the semiconductor parameter analysers like the 4145 and subsequent models which are really a collection of SMUs and the ability to sweep and graph the results.

The latter can be used for characterising all manner of things from a simple diode to a optocoupler to a complete functional block. They are certainly not commonly used by amateurs, but if you have one it's surprising how often you find yourself powering it up and checking if a device really does what its spec sheet says.

And yes you can buy them still, but they are not (and never were) cheap: https://www.keysight.com/gb/en/products/parameter-device-analyzers-curve-tracer.html
 

Offline alm

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #41 on: February 21, 2023, 09:00:51 pm »
And yes you can buy them still, but they are not (and never were) cheap: https://www.keysight.com/gb/en/products/parameter-device-analyzers-curve-tracer.html


Neither where the "simple" curve tracers like the Tek 576 back when they were new. According to TekWiki, the 576 sold for about $17k in 2022 dollars in 1969, and $40k in 2022 dollars in 1990. I highly doubt many hobbyists have them. Now of course both used curve tracers (if you can find a working one) and old used semiconducter parameter analysers like the HP 414x series are within the reach of some hobbyists.

Online Martin72

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #42 on: February 21, 2023, 11:21:21 pm »
This is the point.
Tracers are unpopular not because they are no longer needed, but because they are simply expensive.
A few years ago, we (the company) had the problem of being taken in by fake goods.
BUZ84...A classic that we need again and again for older projects.
It turned out that one batch already broke down at about 280V, instead of at 800V, as stated in the data sheet.
You can't get that out with a simple diodentest or an Atlas DCA75 or similar with low voltage.
For a "simple" (I had to smile earlier) TEK576 with its test voltages up to 1500V, this is not an issue.
Unfortunately, we didn't have that, we solved it differently.
 
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Offline timeandfrequency

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #43 on: February 22, 2023, 02:00:10 pm »
Hi Martin72,

[...]
It turned out that one batch already broke down at about 280V, instead of at 800V, as stated in the data sheet.
You can't get that out with a simple diodentest or an Atlas DCA75 or similar with low voltage.
For a "simple" (I had to smile earlier) TEK576 with its test voltages up to 1500V, this is not an issue.
Unfortunately, we didn't have that, we solved it differently.
For very basic breakdown voltage test of transistors and diodes (up to 1000VDC), this small device makes the job. It's handy and lightweight.
User manual here.
« Last Edit: February 22, 2023, 02:15:20 pm by timeandfrequency »
 

Offline mbrennwa

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #44 on: February 24, 2023, 07:23:43 pm »
Looks like I was missing out by not looking at this forum more often. Anyway, here's my curvetracer: https://pypsucurvetrace.readthedocs.io

PyPSUcurvetrace takes a somewhat different approach than most other curve-tracer projects that require some specific hardware / board to work. PyPSUcurvetrace is a software toolbox that controls programmable power supplies to set and read the voltages and currents at the DUT. This means you can make a curve tracer from PSUs that are available off the shelf, and you choose the PSU units that suit your application: small transistors, power transistors, vacuum tubes, etc.

The PSUs don't need to be expensive "high end". For example, two RIDEN 6006P units can be had for about $300 or less, and will make for a very decent curve tracer setup!

PyPSUcurvetrace also allows controlling the temperature of the DUT during curve tracing. I attached an example of an IRFP150 power FET measured at 30°C, 50°C and 70°C.

PyPSUcurvetrace not only allows measurement of the curves, but also has post-processing tools for high-quality curve plotting and to determine the DUT parameters from the raw data files (e.g., bias voltage/current for a given operating point, gain parameter, output conductance). More tools like curve matching/pairing of parts are in the works...
 
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Offline pizzigri

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #45 on: November 11, 2024, 06:06:24 am »

What should have changed that it no longer requires a Curve Tracer ?
I am currently building one based on Arduino.

Hello Martin, sorry to resurrect this thread, did you finish the tracer you mentioned? I’m really interested!
Franco
 

Online coppercone2

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #46 on: November 11, 2024, 06:25:39 am »
they are awesome you actually know what is going on  :-//

I think if you think you don't care it means that your not doing difficult circuits or used to working with serious copypasta engineering / generic clone designs

I personally never used one because I was mostly experimenting with op-amps and integrated circuits that are too complex. Now I am starting to get interested in more customized and special circuits (and attempting more difficult equipment repairs) so its a great thing to own.
« Last Edit: November 11, 2024, 06:31:01 am by coppercone2 »
 

Online guenthert

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #47 on: November 11, 2024, 09:16:19 am »
Why would one want to use a curve tracer in 2023?

   No idea, but when the company I worked for moved into flashy new office buildings at Santa Clara square in 2019, ADI became our neighbor.  They were a bit slow to move (well, I suppose, moving electronics lab equipment is more cumbersome than some server racks) and for a few weeks I could peak into their lab on ground floor.  I saw there an old (seventies?) Tektronix curve tracer and was wondering if they were about to dispose of it and I could score.  Then however I saw half a dozen more of those in as many work stations.  Clearly, they were still using those, heaven knows what for.  I never figured that out as shortly afterwards they frosted the windows at eye level.
 

Offline RoGeorge

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Re: So what do you do when you need a modern transistor curve tracer?
« Reply #48 on: November 11, 2024, 09:36:29 am »
Clearly, they were still using those, heaven knows what for.  I never figured that out as shortly afterwards they frosted the windows at eye level.

https://duckduckgo.com/?t=ffab&q=periscope&iax=images&ia=images
 ;D


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