RE: [IBIS-Users] V/T Window adjustment

Hello Shiv,

I suggest that you remove the leading common delay from the VT tables.
If you do treat the MIN, TYP and MAX models independently -- i.e. strip
the leading delay from the MIN, TYP, MAX models independently -- then
you will be able to run the models at a higher frequency.

Cary Mandel
Mentor Graphics. 

-----Original Message-----
From: owner-ibis-users@server.eda.org
[mailto:owner-ibis-users@server.eda.org] On Behalf Of Shiv Harit MATHUR
Sent: 29 May 2007 11:14
To: ibis-users@server.eda.org; ibis-users@server.eda.org
Cc: Shiv Harit MATHUR
Subject: [IBIS-Users] V/T Window adjustment

Hello Experts,

I am trying to model a buffer whose freq of operation is 1.5Ghz (time
period = 666ps).
While extracting the V/T curve for the buffer we need to take up a
window of not less than 800ps to cover all the three waveforms. The
buffer delay in MAX,NOM and MIN CORNERS is 130.31ps, 228.44ps and
424.08ps respectively.

Please find the snapshot view of the rising output waveform "TXP" of the
buffer in three corners, "SB" is the Input data given to the buffer (the
  delay values are almost same for the falling stimuli also)

Now the problem is that if I extract and dump these values in the IBIS
model, the model will certainly fail in the worst and typical cases as
the bit time is 333ps (< V/T window size). Although it will give a good
match only if MAX corner is considered.

Can anybody please suggest, what could be done for this case in order to
model the behaviour of the buffer correctly in all three corners ?

Regards
Shiv Harit Mathur
STMICROELECTRONICS PVT LTD
INDIA

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