Is it possible to increase the ADM7150 output voltage to 12V using this kind of circuit?
will the output noise increased?
what is the max and min value of r1 and r2 can be used?
If you really need low noise (<2uVrms or even <20uVrms) then the LM317 will not be able to achieve that.
Most LM317 have noise levels of 50-100 times per volt or 1000x the noise if you are trying to generate 12V.
Could you use the ADP7118 or ADP7142? This will have noise around 12uV at 12V output.
See the DESIGN EXAMPLE OF USING THE NOISE REDUCTION NETWORK WITH THE ADP7142
in the following app note:
ADI's new LDOs have this ability to use fixed voltage LDOs, like a 5V preset version, and raise it's voltage above the set point instead of having to use the 1.2V version of the LDO to do that. Noise is improved by setting the reference voltage internally in addition to the noise reduction technique described in the app note.
Theoretically you could do something like this, but your caps should go to ground.
Yes, the noise will increase. The R1/R2 have to draw the min load current required by
the regulator, which is zero for the 7150. If they are too low, all the current goes into
the divider and you have nothing left for your load.
Best to use an LM317 three terminal adjustable that was designed for this.
Also see the three app notes.