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ADP3303 ERR and reverse-polarity protection

Question asked by LThode on Jan 20, 2014
Latest reply on Mar 6, 2014 by gmorita

I'm looking to use the ADP3303 in a relatively low-current (<< the 200mA limit of the '3303) 5->3.3V application, with a large capacitor on the output to hold up the 3.3V supply for a short period of time after 5V dies so that the system can log the power-fail event to NVM before all the lights go out.  However, the datasheet leaves a few things unanswered, which is why I'm posting here.

 

  1. What is the voltage threshold at which the ERR pin flags?  (A percentage of Vout(nom) or Vin(dropout) will suffice here.)
  2. How long does it take from the threshold being reached to the ERR pin going LOW? (Propagation delay, basically.)
  3. What happens to the ADP3303 when Vin is driven to 0V while Vout is held up? (Assume that the SD pin is tied to Vin.)  Does it fry, act as a diode from OUT to IN, or sit there and be an almost-open-circuit? (If it is the latter, how much leakage current can I expect at OUT?)

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