Resistor TC; was Syncronous Switchers

[[email protected]]

From the thread, comment by John Larkin:

I've mentioned the Susumu thinfilms here more than once. We have a

huge "tower" sample kit that the local Susumu rep dropped off, must be

a couple thousand resistors. We buy parts down to 0.05% and we are

measuring TCs in the 5 PPM range.

That's another topic in itself.

Take a specified 25ppm TC resistor part, what would be the value used for worst case calculations. The 25ppm is probably a long way from the actual TC due to manufactor "cover my ass" policies.

Anyone have numbers for that and how the trend/graph typically looks?

Do part from same lot or even manufactor tend to track, so the resultant TC of say a resistive divider isn't just the squared root sum of the individual TCs?

Regards

Klaus

 

[John Devereux]

From the thread, comment by John Larkin:


That's another topic in itself.

Take a specified 25ppm TC resistor part, what would be the value used
for worst case calculations. The 25ppm is probably a long way from the
actual TC due to manufactor "cover my ass" policies.

Anyone have numbers for that and how the trend/graph typically looks?

I did this not so long ago

<http://ee.devereux.me.uk/resistor-tempco.png>

(There are numbers on the graph scale but may be hard to see depending
on browser settings).

There were two types of resisor, vishay Z201 series "ultra high
precision" and some "Econistor" 3ppm parts marketed by Rhopoint in UK.

Of course this was just for some particular samples.

Do part from same lot or even manufactor tend to track, so the
resultant TC of say a resistive divider isn't just the squared root
sum of the individual TCs?

Yes, I believe this is usually the case.

 

[[email protected]]

[email protected] writes:








I did this not so long ago



<http://ee.devereux.me.uk/resistor-tempco.png>



(There are numbers on the graph scale but may be hard to see depending

on browser settings).



There were two types of resisor, vishay Z201 series "ultra high

precision" and some "Econistor" 3ppm parts marketed by Rhopoint in UK.

It shows fine in my brower, nice measurements

Thanks

Klaus