The LM4510 datasheet lists shutdown current in small fractions of microamps. Typically, chips don't have parameters with values in the nanoamp range because it's too difficult to measure such small currents quickly in mass production. Also, this is a couple orders of magnitude lower than the shutdown currents for most DC/DC converter chips. Is this a typo in the datasheet, or is the shutdown current really 0.002 uA typical, 0.050 uA max.?