Two important terms when referring to Leakage Current are Source Off or Is(off), and Drain Off or Id(off). Is(off) is the algebraic sum of leakage currents into or out of an Off channel source input and is predominately caused by parasitic reverse-bias diode junctions. Id(off) is the algebraic sum of leakage currents into or out of a disabled/off channel drain input and is mainly due to parasitic reverse-bias diode junctions.