Sorry, I need to correct myself:
Change:
If you have an Open something model, you will only need two waveform
tables, and the V_fixture should be the same for both either 0V or
0.4V, whatever the pulldown or pullup I-V curve is using.
To:
If you have an Open something model, you will only need two waveform
tables, and the V_fixture should be the same for both either 0V or
0.4V, whatever the voltage for the opposite side supply rail is for
the output stage.
Thanks,
Arpad
======================================================================
From: ibis-users-bounce@xxxxxxxxxxxxx [mailto:ibis-users-bounce@xxxxxxxxxxxxx] ;
On Behalf Of Muranyi, Arpad
Sent: Monday, January 09, 2017 11:16 AM
To: ibis-users@xxxxxxxxxxxxx
Subject: [ibis-users] Re: [ibis] PullDown data Range
Ahmed,
Regarding V_fixture, if the buffer is not Open Source or Open Sink,
you should have four V-t tables, two rising and two falling. For
each of the rising and falling tables you should have a high and a
low V_fixture. So one rising waveform should have 0V and the other
should have 0.4V, and the same way, one falling waveform should have
0V and the other 0.4V. These voltages should match the voltages to
which the pullup and pulldown I-V curves are connected.
If you have an Open something model, you will only need two waveform
tables, and the V_fixture should be the same for both either 0V or
0.4V, whatever the pulldown or pullup I-V curve is using.
I don’t think you should use the higher clamp reference voltage for
the V_fixture, because that is not related to what the driver’s
driving transistor (I-V curve) is using.
I hope this helps,
Arpad
======================================================================
From: ibis-users-bounce@xxxxxxxxxxxxx<mailto:ibis-users-bounce@xxxxxxxxxxxxx>
[mailto:ibis-users-bounce@xxxxxxxxxxxxx] On Behalf Of Ahmed Essam
Sent: Monday, January 09, 2017 9:21 AM
To: Mike LaBonte <mlabonte@xxxxxxxxxx<mailto:mlabonte@xxxxxxxxxx>>
Cc: ibis-users@xxxxxxxxxxxxx<mailto:ibis-users@xxxxxxxxxxxxx>
Subject: [ibis-users] Re: [ibis] PullDown data Range
Hi Mike,
Thanks a lot for your reply.i get confused after your reply.
My Thoughts was that we need to get PULLDN data in the range from (-0.4V to
0.8V) as that will be the voltage on transmission line.
i was using V_fixture=0.4V in [Rising waveform] . Will it be right to use
V_fixture=1.8V as for PULLDN data? and what will be the voltage used in
[Voltage Range] and [POWER CLAMP Reference] ?
Can u elaborate that point,please?
i have another question about the range of voltages [-VCC - 2*VCC ] which
should be used in TYP,MIN,MAX in gathering I-V data if my supply voltage is
[TYP,MIN,MAX]=[1.8,1.52,1.98]?
Thanks,
Ahmed
On Mon, Jan 9, 2017 at 4:41 PM, Mike LaBonte
<mlabonte@xxxxxxxxxx<mailto:mlabonte@xxxxxxxxxx>> wrote:
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>
[mailto:ibis-bounce@xxxxxxxxxxxxx<mailto:ibis-bounce@xxxxxxxxxxxxx>] On Behalf
Of Ahmed Essam
Sent: Sunday, January 08, 2017 6:57 AM
To: ibis@xxxxxxxxxxxxx<mailto:ibis@xxxxxxxxxxxxx>;
ibis-users@xxxxxxxxxxxxx<mailto: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
