20uv ldo

I am going to use MAX883 low drop out voltage regulator for a PLL design using MC145170. I am concerned about the noise that this regulator is going to introduce in the circuit. The data sheet shows output noise voltage to be 250 micro Volt RMS.
Is it fine to use this regulator for this PLL?

I think 250uV RMS is a little bit too much. Depends by your operating conditions that include regulator input and output voltage, bandwidth, load, quality of capacitors, etc.
I would go for LT1763, which have 20uV RMS
http://www.linear.com/pc/downloadDoc...55,P1778,D3903