using these parameters:
vinmin=10v
vinmax=13.2v
vout=6v
iout=1.25a
run webbench
select tps53313
get rfb1=2k
rfb2=18k
Databook calculations show r2=.6/(vout-.6)*r1 so r2 should always be less than r1. Databook defines r1 as vfb to out. Seems to be an error somewhere.
