Susumu resistors

J

John Larkin

Guest
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)
 
John Larkin wrote...
These are the cheap 25 PPM parts.
https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0
https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0
Click to expand...

Is that their RG series, or what?


--
Thanks,
- Win
 
On 16 Aug 2019 22:39:18 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

John Larkin wrote...

These are the cheap 25 PPM parts.
https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0
https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

Is that their RG series, or what?
Click to expand...

Right.
 
On Friday, August 16, 2019 at 8:09:30 PM UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)
Click to expand...

Huh... so is there a value that is totally flat?
The geometric mean is about 10k ohm.
(Unless it's to early for me to do math.)

George H.
 
On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)
Click to expand...

Interesting that they're linear. I infer from the datasheet that
Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude better so I guess they've done a first order correction to a smallish linear tempco like the
Susumus.

--Spehro Pefhany
 
On Sun, 18 Aug 2019 05:34:04 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Friday, August 16, 2019 at 8:09:30 PM UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Huh... so is there a value that is totally flat?
Click to expand...

Not having tested many of them, I'd guess that there is variation from
part to part, and reel to reel. And there is no "totally flat"; keep
zooming the y-axis until it's ugly again.

There are expensive Vishay parts well below 1 PPM. These Susumu's
average around 20 cents.
 
On Sun, 18 Aug 2019 08:12:56 -0700 (PDT), speff <spehro@gmail.com>
wrote:

On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Interesting that they're linear. I infer from the datasheet that
Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude better so I guess they've done a first order correction to a smallish linear tempco like the
Susumus.

--Spehro Pefhany
Click to expand...

Pretty much any thing that's tweaked to zero out the 1st order term
leaves behind a residual parabola.

Best I could trim an oscillator tempco:

https://www.dropbox.com/s/2ykktl5xjoexh1x/CCRO_TC.JPG?raw=1

Most physical things correct pretty well with a 2nd order polynomial.
We correct lots of things with polynomials, in uPs or FPGAs sometimes,
and we generally go 3rd order. Higher orders can get wild.

I'm lately doing "linear" timing ramps with a simple RC, polynomial
corrected. A resistor is sure a nice wideband, stable, cheap current
source.
 
On Sunday, August 18, 2019 at 9:43:08 AM UTC-7, jla...@highlandsniptechnology.com wrote:

Pretty much any thing that's tweaked to zero out the 1st order term
leaves behind a residual parabola.

Most physical things correct pretty well with a 2nd order polynomial.
We correct lots of things with polynomials, in uPs or FPGAs sometimes,
and we generally go 3rd order. Higher orders can get wild.
Click to expand...

If trimming is done anyhow, consider the positive-tempco resistors
that are proportional to absolute temperature. The linear-in-temperature
character CAN be mass-produced easily and cheaply, it just didn't
win the market.

TI used to make a line of PTAT resistors that would have been perfect for this
kind of use. From a materials-science point of view, that's the
stable solution with the simplest correction curve, following Drude model
for resistivity.
 
speff <spehro@gmail.com> writes:

On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Interesting that they're linear. I infer from the datasheet that
Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude better so I guess they've done a first order correction to a smallish linear tempco like the
Susumus.
Click to expand...

https://ee.devereux.me.uk/resistor-tempco.png



--Spehro Pefhany
Click to expand...

--

John Devereux
 
John Devereux wrote...
speff <spehro@gmail.com> writes:
On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Interesting that they're linear. I infer from the datasheet
that Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude
better so I guess they've done a first order correction
to a smallish linear tempco like the Susumus.

https://ee.devereux.me.uk/resistor-tempco.png
Click to expand...

John, how'd you get that tempco data?


--
Thanks,
- Win
 
Winfield Hill <winfieldhill@yahoo.com> writes:

John Devereux wrote...

speff <spehro@gmail.com> writes:
On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Interesting that they're linear. I infer from the datasheet
that Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude
better so I guess they've done a first order correction
to a smallish linear tempco like the Susumus.

https://ee.devereux.me.uk/resistor-tempco.png

John, how'd you get that tempco data?
Click to expand...

Hi Win

HP3458A 4-wire measurement and my environmental chamber (beer fridge) :)

IIRC I used a keithly 2001 with an RTD to get the temperature, and some
python script to collect the data.

In 2012, when I must have had time for the fun stuff.



--

John Devereux
 
On Sunday, August 25, 2019 at 9:50:14 AM UTC-4, John Devereux wrote:
speff <spehro@gmail.com> writes:

On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Interesting that they're linear. I infer from the datasheet that
Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude better so I guess they've done a first order correction to a smallish linear tempco like the
Susumus.

https://ee.devereux.me.uk/resistor-tempco.png
Click to expand...

I searched for Z-210 resistors... no luck. can you give me a bit more of the part number?

Thx,
George h.
--Spehro Pefhany

--

John Devereux
Click to expand...
 
On Monday, August 26, 2019 at 9:55:52 AM UTC-4, Winfield Hill wrote:
George Herold wrote...

I searched for Z-210 resistors... no luck.

Vishay Z201, $16 each.


--
Thanks,
- Win
Click to expand...

Thanks Win, (a silly typo on my part.)
GH
 
On Sunday, 25 August 2019 09:50:14 UTC-4, John Devereux wrote:
speff <spehro@gmail.com> writes:

On Friday, 16 August 2019 20:09:30 UTC-4, John Larkin wrote:
These are the cheap 25 PPM parts.

https://www.dropbox.com/s/uja0rrbvmlhf108/Susumu_1.jpg?dl=0

https://www.dropbox.com/s/g62npaiak1fawum/Susumu_2.jpg?dl=0

(actually a test post, but with some content)

Interesting that they're linear. I infer from the datasheet that
Z-foil resistors have more of a parabolic curve.

Of course they're something like two orders of magnitude better so I guess they've done a first order correction to a smallish linear tempco like the
Susumus.

https://ee.devereux.me.uk/resistor-tempco.png




--Spehro Pefhany

--

John Devereux
Click to expand...

Thanks, some pretty ugly curves there.

--Spehro Pefhany
 
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