[SI-LIST] Re: target impedance profile

 =C7=C1=B8=AE=C3=A7=B8=DE=C0=CF
=09 =09 

In my case, 

  

If any system has 16 bit data= , I do simulation for current profile. 

For worst case, I make spice = circuit all 16 bit driver and receiver and do
simulation such SSN 

, = then measure the current profile via time domain. 

V(t)*ripple tolera= nce =3D Z(target) I(profile) 

I set the "output variable" lice Z(targ= et) =3D V(t) * ripple
tolerance/I(profile) 

Someone use the stimulus = as random source. 

  

Good luck. 


---------- =BF=F8=BA=BB =C6=ED=C1=F6 ----------
=BA=B8=B3=BD=BB=E7= =B6=F7: Steve Waldstein
=BA=B8=B3=BD=B3=AF=C2=A5: 2008/5/24 1= 9:47:59
=B9=DE=C0=BA=BB=E7=B6=F7: "'ZHENGGANG CHENG'";si-list@xxxxxxxxxxxxx
=C1=A6=B8=F1: [SI-LIST] Re:= target impedance profile

Zhengang,We took v(t) =3D = Inverse FFT (Z(f) x I(f)) to look at the time
domain noise.Remember to have= both the real and imaginary (or magnitude and
phase)portions of Z(f) and I= (f) so the coherency of the noise components
add orsubtract properly when t= he Inverse FFT is
performed.Steve-----Original Message-----From: si-list-bo=
unce@xxxxxxxxxxxxx[mailto:si-list-bounce@xxxxxxxxxxxxx] OnBehalf Of ZHENGG=
ANG CHENGSent: Saturday, May 24, 2008 5:27 PMTo: si-list@xxxxxxxxxxxxxxxxxx=
ct: [SI-LIST] target impedance profileHi all,It seems many SI engineers are=
using the method described below to definethe target impedance profile for=
PSD:Z(f) =3D 0.05*V_DC/I(f) or Z_target=3D0.05*V_DC/Ima= x(f)Z(f)---target
impedance profile at freq f;Z_target---target impedanace = at all
freq;0.05---allowed tolerance;V_DC---power raill;I(f) ---current pro=
file;Imax(f)---max I(f)---generallt 0.5Imax(t).But this setup does not guar=
antee the overall noise is 5%. All it does ismaking sure noise at each of =
the frequency of interest is less than 5%. Intime domain, the combined con=
tent has the possibility of bigger than 5%.So is there a better way to defi=
ne target impedance profile?Thanks,Zhenggang Cheng-------------------------=
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=09 =09[IMG][1]
=C7=DA=B5=E5=C6=F9=C0=C7 =BA=AF=C3=B5=BB=E7.. =09[IMG][3]
=B9=DA=C1=F6=BC=BA =B1=CD=B1=B9! =BA=B8=B0=ED= =BD=CD=BE=FA=BE=EE!![4]
=09[5]
=BB=C7=BA=FC=C0=CC.. =B1=D7=B4=C2 =BD=C7=C1=B8= =C0=CE=B9=B0=C0=CC..[6]
=09[7]
=B5=BF=BD=C3=BF=A1 =BB=E7=B6=F3=C1=F6=B4=C2 = =B5=CE=B0=B3=C0=C7 =BA=F4..[8]
=09[IMG][9]
=BE=EE=B8=A5=B8=B8=BA=B8=BC=BC=BF=E4[10] =09 =09=09=09 =09 

--- Links ---
   1 3D
   2 3D"http://qtv.freechal.com/movie/QTVMovieView.asp?docid=
   3 3D
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   8 3D"http://qtv.freechal.com/movie/QTVMovieView.asp?docid=
   9 3D
  10 3D"http://19.qtv.freechal.com/";
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