Ahmed,
This is a great question, one that might trigger a discussion about
improving the clarity of the IBIS specification. The rule you refer to is in
Table 16 on page 165 of IBIS 6.1 <http://ibis.org/ver6.1/ver6_1.pdf> , in
the “NOTES ON DATA DERIVATION METHOD” section. We might need to improve that
section as part of our ongoing IBIS 6.2 update, particularly because the
table uses GND and POWER to refer to voltage values. For IBIS 6.2 we intend
to refer instead to IBIS keywords that are properly defined as voltage
values.
For the time being I would recommend extending any [Pulldown] and [Pullup]
tables using 1.8V as the basis in your specific case, even if you have to
extrapolate to get beyond 0.4V. The reason is that tools will have to sum
the tables over the full range to form the data actually simulated, and it
would be best not to make assumptions about how the tools will extrapolate
the “missing” data beyond 0.4V.
Mike
From: ibis-bounce@xxxxxxxxxxxxx [mailto:ibis-bounce@xxxxxxxxxxxxx] On Behalf ;
Of Ahmed Essam
Sent: Sunday, January 08, 2017 6:57 AM
To: ibis@xxxxxxxxxxxxx; ibis-users@xxxxxxxxxxxxx
Subject: [ibis] PullDown data Range
Hi All,
i am working on ibis model for an output buffer.The ESD devices is connected
to I/O supply equal to 1.8V .while the buffer is connected to supply equal
to 0.4V.
I defined the voltage range and power clamp reference as follows
[Voltage Range] 0.4 NA NA
[POWER Clamp Reference] 1.8 NA NA
Shall the pulldown data range be( from -0.4V to 0.8V) ? or ( from -1.8V to
3.6V) ?
Thanks,
Ahmed
