Design ultra low noise from 12V to 1.2V 1.8V 2.5V

[noisepic]

I need design ultra low noise from 12V power supply to lower voltage for IO and processor. Which part is most suit for this circuit!

[robertferanec]

What does it mean ultra low noise and what are the currents? For processor and IO application you should be fine with standard switching power supplies.

PS: Very often, if I need a low noise power supply, I use a step down switching power supply and then I use Linear regulator after that.