One of my microcontroller projects requires dual outputs, 5V and 3.3V.

Instead of using a dedicated LDO for 3.3V, can a zener get the job done efficiently? Wouldn't that be easier and equally stable?

Any reason to stick with an LDO?

Thanks.  

*Just so you know, current required for both voltages is 200ma.*  

*Supply voltage from USB or 3.7V battery with boost.*