How to regulate voltage from a 5V wall adapter?


I want to power a small circuit which requires 5V/200mA from a regular 5V wall adapter.

Which components would you recommend for a good, stabilized 5V output?

Current candidates are:

  • L4931 (3-pin T092)
  • Pololu S7V7F5 step up/step down power regulator (complete circuit, 9 x 12 x 3mm).

Besides size, costs and voltage input range, which solution will provide the most stable, clean and precise voltage?

Thank you for helping.


A modern 5v wall adapter alone will output regulated 5v. If it does not, throw it in the trash, walk down to the nearest convenience store, and buy another phone charger (if you don't have spares kicking around already; I have a bin full of the damned things)...

A linear regulator has a minimum dropout, ie, it needs a voltage higher than 5v (how much higher is specified in the datasheet), while the step-up/down converter will just waste power turning 5v into 5v.

Thank you!