Continue to Site

Welcome to EDAboard.com

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.

Register Log in

Problem in designing PLL [hlp]

Status
Not open for further replies.
N

No one

Full Member level 5
Full Member level 5
Joined
May 11, 2005
Messages
287
Helped
4
Reputation
8
Reaction score
2
Trophy points
1,298
Activity points
3,425
Hello Everyone;
Suppose that in designing a PLL, maximum output voltage of charge pump is about 6V. But the VCO tuning voltage is up to 14V. How we can design the PLL?
 

it is a hard problem , i think u should check to see another VCO

khouly
 

    N

    No one

    Points: 2
    Helpful Answer Positive Rating
Khouly wrote:
it is a hard problem , i think u should check to see another VCO
Click to expand...
.

Have you any suggestion for 800-1400MHz VCO with tuning voltage of less than 6V?
 

I amnot sure what you are trying to say. If the only VCO you can find has a 14 V tuning range, you are going to need an op amp to provide DC gain.

If you do not have a 18 volt power supply to power the op amp, you are going to have to provide some sort of switching regulator to step up the voltage.


This is precisely why some VCO's use hyper abrupt tuning varactors, so you get almost all of the frequency change in the first 4 or 5 volts of tuning.
 

    N

    No one

    Points: 2
    Helpful Answer Positive Rating
There are numerous app notes on active loop filter design. You should be able to find them at national or analog. An active loop filter basically uses an opamp to amplify the loop filter voltage.

There are too many design elements to list here, but an active loop filter with an opamp is the standard way to handle CP/Kv mismatch.

C
 

    N

    No one

    Points: 2
    Helpful Answer Positive Rating
U can design ur PLL using the WEBENCH tool it is almost perfect. U can find this tool on national semiconductor website.
Good Luck
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top