stephenryan2525:
I am getting my 4.30v ref from a potentiometer connected to 5v and GND
It was set to output 4.30v when laptop PSU was connected. When powered by USB its drops to 3.94v so adjustment is required.
So your reference is at susceptible to your 5V supply variations.
Try a TL431 programmable ref IC setup as a constant voltage ref. this will keep your setup Vref constant no matter how your 5V fluctuates.
http://www.ti.com/lit/ds/symlink/tl432a.pdf
Tom... 