Electronics > Metrology

Statistical arrays

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doktor pyta:
Dear colleagues,

First of all we heared about interesting properties of TaN resistors statistical arrays.
There are some CERN- related papers describing developments made by great Mr John Pickering.
He seems to like using this technique as it does the job at reasonable price and in relatively simple, elegant way.
Inspired by him I made simple setup to see what can be achieved using off the shelf component.
I used 8x10k NOMCA in SOIC 16 package and wired the circuit as shown on the drawing below.
It is thermally balanced divider by 10.

The setup takes advantage of HP 34401A in ratio mode, Data Precision 8200 as (4-wire) voltage source, thermocouple thermometer.


P.S.  please post examples of statistical arrays applications (schematics) that You know about

Echo88:
Wavetek 7000-series voltage reference used statistical dividers model Vishay-TDP: https://www.eevblog.com/forum/metrology/teardown-voltage-standards/msg902910/#msg902910
https://www.vishay.com/docs/60045/tdp.pdf
http://www.vishay.com/docs/60117/nomca.pdf

branadic:
I was always concerned about the tracking t.c. of 5ppm/K for Vishay TDP16031002 or NOMCA16031002. I wonder if TaN statistical arrays are any better. But even if they were, they seem to be unobtanium. I once searched for more information, but wasn't able to find the real hints. So any link to related papers are welcome.

https://www.ebay.de/itm/1pcs-TDP16031002BUF-Vishay-Resistor-Networks-Arrays-10Kohms-16/263962507025
https://www.ebay.de/itm/1pcs-NOMCA16031002ATS-Vishay-Resistor-Networks-Arrays-16-pin-10/263957703582

-branadic-

doktor pyta:
Now watch this:

1. division ratio error: +12ppm (no adjustment!)

2. T amb=25'C, T heat=50'C
average T.C. of division ratio: 0.32ppm/'C

3. Thermal shock 25'C; -20'C; 25'C
division ratio change: 0ppm

4. Thermal shock 25'C; 100'C; 25'C
division ratio change: 0ppm

Keep in mind 1ppm is a resolution of my simple but very stable setup (further measurements need to be done).


To be precise I used P/N NOMCA16031002ATS bought from Farnell.

d-smes:
When you did thermal shock, did you go from 25C to -20C, back to 25C, and then make the measurement?  Or did you go from 25C to -20C and then make the measurement?  I just wondering why the TC didn't show up in the ratio measurement...

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