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.

how to check the stability of SC CMFB ?

Status
Not open for further replies.

safwatonline

Advanced Member level 4
Joined
Nov 19, 2005
Messages
1,341
Helped
219
Reputation
438
Reaction score
48
Trophy points
1,328
Location
EGYPT
Activity points
9,038
SC CMFB

how to check the stability of sc CMFB ?
 

Re: SC CMFB

As far as I remember , the SC CMFB by itself is always stable(it doesn't add poles to the loop), what u need to check is the stability of the rest of the CMFB loop.
 

    safwatonline

    Points: 2
    Helpful Answer Positive Rating
SC CMFB

i meant being discrete time how to see PM and GM , do poeple usually use PSS + PAC or what?
 

Re: SC CMFB

MSSN said:
As far as I remember , the SC CMFB by itself is always stable(it doesn't add poles to the loop), what u need to check is the stability of the rest of the CMFB loop.
Is it true that the SC CMFB doesn't add pole to the loop?
 

Re: SC CMFB

safwatonline said:
i meant being discrete time how to see PM and GM , do poeple usually use PSS + PAC or what?

you can use a ideal cmfb instead to see PM and GM
 

    safwatonline

    Points: 2
    Helpful Answer Positive Rating
SC CMFB

hi dodoro, can you tell me after use a ideal cmfb ,where i can put the ac source to see PM and GM ,
since it is now a close loop.
 

Re: SC CMFB

Use this,

.op time1 time2

together with

.ac 1 1G 10

to force AC analysis at two different transient time points (time1 and time2), and choose time1 and time2 at the middle of each of the two clock phases.

put an AC loopgain src in your CMFB loop and you'll have the loop-gain in both loading conditions of your S-C CMFB circuit.

Eldo and spectre have different syntax for this. LTspice can do this nicely too.
 

    safwatonline

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top