Originally Posted by peterpan188
I am a little confused about IC3. I thought we can't really use the fixed voltage regulator, REG101UA-5, REG102UA-5, for direct USB powered option. The part list note says that, it doesn't really regulate. Instead we have to use REG101UA-A, or REG102UA-A as adjustable regulator, and regulate it down to 4.8V using R31 and R32. But at the same time, the part list tells that they are only mandatory for all configurations except Direct USB. What is right? I am planning to use the DAC always USB powered, what should I get?
Also I didn't see anywhere explanation of REG101UA-A/REG102UA-A vs REG101UA-5/REG102UA-5. Text near Vout formula only says that REG101 has higher Vref than REG102. I ordered REG101UA-5 because it was first in the list. May be a little more details on IC3 selection for different power options will help others.