A：Many reasons possible: current limit has been activated, thermal shutdown has been exceeded, dropout voltage spec not obeyed,
ESR of caps rules not obeyed, etc.
2.Q：How may I obtain the reference voltage out of an adjustable LDO?
A：Hook the ADJ pin directly to Vout.
3.Q：What is the accuracy of my LDO?
A：The accuracy of the LDO is the VREF (ADJ) voltage accuracy. It is typically 1% at certain conditions. If a resistor divider is used for an
ADJ device, the total accuracy will be affected by the external resistance tolerance.