Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.
Just search for middlebrook's method. Connect a very big inductor from the feedback node back to your opamp input (its a dc short and ac open circuit) . add an ac voltage source to your input 1 v AC and run ac analysis by sweeping the frequency. observe the gain and phase plots and let me know...
http://www.geocities.com/fudinggepll/index.html
http://www.geocities.com/fudinggepll/PLLProj.pdf
First link takes you to the page , the second is the link to the document on PLL's which i think is very good.
amarnath
Yes i understand, thats why i said it all depends on what application the PLL is going to be put to use to. For lower end applications it may not matter as much, but it is good to understand what each parameter does before choosing a value for the same for whatever application it may be.
amarnath
choosing a charge pump current
wn=sqrt(ip*kvco)/(2*pi*N*C1).Fit in the other parameters like divider ratio, gain of the VCO and the loop filter capacitor. Overall the pump current is chosen based on noise requiremtns ,BW,lock time etc.You can refer to the book PLL frequency synthesizers by...
yes you need to use trimming to trim the frequency across corners. But variation across V-T can also be high enough, but atleast you can remove the variation across process by having sufficient trimming.
amarnath
Hi Mouzid, please do a google search for "Fuding Ge pll thesis"
There you will get this thesis. Yes the loop filter needs to be designed so that the PLL locks to the input frequencies.You will find the standard design equations in any design book.
Amarnath
to reduce the ripple on the control voltage size the capacitor to filter the ripple.In a second order loop filter the second pole should be sized to filter out the ripple.
in any feedback system the output settles to some value within some error % difference compared to the input. This error reduces but cannot be eliminated, it is less in case of second order PLL.
amarnath
The resistor nullfies the zero if its sized such that it cancels out the zero created by the miller cap. The resistor can also be sized to move the zero to the right half plane to increase the phase margin.
amarnath
Just add a miller cap as in a two stage opamp, this will introduce a zero since you now create another path for the signal to reach the output.Then try moving this zero to the right half if needed to improve your phase margin.
amarnath
This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
By continuing to use this site, you are consenting to our use of cookies.
