very low noise 3.3 V voltage regulator

[raebrm]

Hi,

At the moment I am trying to design a very low noise power supply for a 7GHz comms circuit. The best power design I got is based on ADP3338 attached below. The circuits require 3.3V and takes in 150 mA current max. The smaller the voltage regulator circuit is, the better.

Have u got a voltage regulator design that gives very stable voltage + very low noise rejection?

Thanks

 

[biff44]

There are two tricks for low noise voltage regulators:

1) choose one that allows you to put an external capacitor across the bandgap reference, such as LM723, NCP623, etc

2) Have enough input shunt capacitors (and maybe input series inductance or small resistance) to form a lowpass filter for any input noise above 10 KHz (where most regulators stop "regulating")