PLL loop filter selection

bandpass

As we know, the number 1 LPF in schematic is the well known circuit.
0 Y4 r' Y) {% W) d3 y
   But some application is like the number 2 LPF in schematic. Any commetions about it ?
- [7 \7 R" L' K! R
   Any discussion is appreciated.

circuitman5566

thank you so much! thank you so much! thank you so much!