d123
Advanced Member level 5
Hi,
Is there a "best" position for trimpots in adjustable voltage regulator and adjustable voltage reference feedback paths?
Asking because thinking of feedback current that is seen across R1 and that in datasheet and app note calculations is considered important/relevant for calculating Vout.
I would have thought that B or C as I understand R2 sees less current than R1, but maybe it makes no difference whatsoever whether the trimpot is placed in position A, B or C. Is there any difference between B or C in practical terms, too?
The question(s) is (are) related to issues such as temperature drift, perhaps noise if that is affected or in any way pertinent, and other minutae beyond my level of implementation successfully but of interest all the same.
Just slip in a bonus question: Using 100ppm resistors in conjunction with 200ppm trimpots - (for someone who makes little circuits at home...) it's a trivial concern design-wise and irrelevant to the circuit long-term stability of the accuracy and not worth worrying about, isn't it?
Thanks.
Is there a "best" position for trimpots in adjustable voltage regulator and adjustable voltage reference feedback paths?
Asking because thinking of feedback current that is seen across R1 and that in datasheet and app note calculations is considered important/relevant for calculating Vout.
I would have thought that B or C as I understand R2 sees less current than R1, but maybe it makes no difference whatsoever whether the trimpot is placed in position A, B or C. Is there any difference between B or C in practical terms, too?
The question(s) is (are) related to issues such as temperature drift, perhaps noise if that is affected or in any way pertinent, and other minutae beyond my level of implementation successfully but of interest all the same.
Just slip in a bonus question: Using 100ppm resistors in conjunction with 200ppm trimpots - (for someone who makes little circuits at home...) it's a trivial concern design-wise and irrelevant to the circuit long-term stability of the accuracy and not worth worrying about, isn't it?
Thanks.
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