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:: DIP / SOIC package surface reistance

Bob pease' video about femtoampere things gives us a very interesting look into package inter pin insulation resistance.
What's All This Femtoampere Stuff, Anyhow?
from various ic specifications we can draw up inter pin dimensions to estimate further, we could estimate what kind of insulation tolerances the packages have, by counting the number of squares between the pins. as surface resistivity is characterized by "ohm.square" and using the thickness of the pin as a way to visualize the number (as seen in the below estimation by drawing diagonal lines)
DIP inter pin overview
due to manufacturing tolerances, the pin maybe 10mils thick or 15mils thick. 30 or 40 mils between pin. this seem to suggest the plastic DIP worse case insulation tolerance needs to go as high as 500Tohm.square best case tolerance 240Tohm.square
SOIC inter pin overview at worse tolerance, 290Tohm.square at best tolerance, 150Tohm.square
MSOP inter pin overview MSOP worse tolerance 560Tohm.square
if the tol…

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