DLL transfer function

[nandu]

dll transfer function

Hi all
I would like to know the loop gain of a typical charge pump DLL. Also, I have seen the gain term \[ K_{VCDL} \] being used often, but dont know its exact meaning. Does it depend on the number of delay stages in the DLL? And does \[K_{VCDL} \] have any upper and lower limits in order to ensure stability. Im guessing it wont because a charge pump DLL will only be a 1st order system and hence wont oscillate.

 

[CherryQ]

kvcdl dll

No, this is the voltage to delay time gain of your VCDL. You can see its unit is sed/V. If you have N delay cells, each one has the same voltage to delay time gain, so Kvcdl is N times of that.

 

[lijianheng]

transfer function dll

CherryQ is right. Here is a paper link maneatis96b.pdf about DLL. Hope this helps.

 

[stoned]

kvcdl dll

Hi all
I would like to know the loop gain of a typical charge pump DLL. Also, I have seen the gain term \[ K_{VCDL} \] being used often, but dont know its exact meaning. Does it depend on the number of delay stages in the DLL? And does \[K_{VCDL} \] have any upper and lower limits in order to ensure stability. Im guessing it wont because a charge pump DLL will only be a 1st order system and hence wont oscillate.

Hi nandu,
U got it, DLL is 1st order system, so it is unconditional stable. And you should consider you delay time is satisfy you requred in every coner when your VCTRL is changing.

Stoned