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manissri
Joined: 16 Apr 2005
Posts: 273
Helped: 6
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 13 May 2005 8:53 settling timeof opamp |
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hi all ..
for u high speed opams in which the fast settling time is needed. i want to know for that opamps why the high UGB ( bandwidth) is needed.
plz reply
manish
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Y.C Park
Joined: 20 Dec 2004
Posts: 47
Helped: 2
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| 13 May 2005 9:07 Re: settling timeof opamp |
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Last edited by Y.C Park on 13 Apr 2006 11:36; edited 1 time in total |
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electronics_kumar
Joined: 29 Nov 2004
Posts: 634
Helped: 24
Location: Tamilnadu
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| 13 May 2005 11:38 Re: settling timeof opamp |
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i think I AM CORRECT BU SAYING risetime*BW =3.5
I WANT KNOW HOE U ARE SAYING RISETIME=SETTLING TIME
Setting time (Rising time ) * 3dB
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Y.C Park
Joined: 20 Dec 2004
Posts: 47
Helped: 2
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| 13 May 2005 13:00 Re: settling timeof opamp |
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HI electronics_kumar
What I say is that only for intuition
Your saying is right.
Setting time is not rising time.
But I mean zero to destinated Voltage rising time.
Could you tell me why risetime*BW=3.5 ?
Thanks
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hebu
Joined: 15 Nov 2004
Posts: 194
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| 27 Jul 2005 9:12 Re: settling timeof opamp |
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I remeber the rule of thumb is Tr=0.35/BW
and it's related to the first order low pass filter and the time constant.
You may get some ideas from the principle of communication wrote by
Zemer.
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jeniffer
Joined: 18 Aug 2006
Posts: 16
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| 24 Aug 2006 4:28 Re: settling timeof opamp |
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| is the Bw mean the UBG?
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chenmy
Joined: 18 Aug 2006
Posts: 17
Helped: 2
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| 24 Aug 2006 17:02 settling timeof opamp |
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Hi,for a 1-pole system,rise time Tr=0.35/BW ,here the BW is the -3dB bandwidth.
For a 2-ploe system, if the phase marging is less than 60 degree, there will be overshoot and settling.What I remember is UBG=2*D*Wn ,here D is the damping factor and Wn is the natural frequency and the settling time is protial to exp(-D*Wn).
Thus,it is clearly that if the fast settling time is needed the high UGB is also needed.
Regards!
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