I'm designing the LTC4079 into a product and am confused regarding the voltage divider equation in the "Feedback Divider Selection" section. At the end of the Vchg equation there is the term (I_FB + I_LEAK). The paragraph under the equation is not clear. How does one figure out these terms and what is the difference between the two. Does the attached plot describe the leakage current through the feedback pin due to the 160mR FBG pin? Should I just estimate this to be 1nA at 25C? If so, how does one come up with the I_LEAK value?