Hi Fabio,
Good question that will spark discussion within the IBIS Committee.
The Notes on Data Derivation Method and possibly the IBIS Cookbook are not
general enough because "GND" and Vss had been assumed to be 0.0 V
The intent is that normal operating range (Vss to Vcc) be added or
subtracted to each of the references to support the unlikely case of a full
reflected voltage for an unterminated buffer.
So, Vcc - Vss = 10.0 V
Sweep Range is 15.0 V to -15.0 V (5.0+10 and -5.0-10)
The a more general sweep range formula would be
Vcc + (Vcc - Vss) to Vss - (Vcc - Vss)
= 2Vcc -Vss to 2Vss - Vcc
Bob
From: ibis-users-bounce@xxxxxxxxxxxxx
[mailto:ibis-users-bounce@xxxxxxxxxxxxx] On Behalf Of Fabio BRINA
Sent: Friday, January 13, 2017 8:37 AM
To: ibis-users@xxxxxxxxxxxxx
Subject: [ibis-users] Voltage sweep in case vss=-vcc
Hello experts,
I'm in the case of a buffer with dual supply, I mean: vcc=5V and
vss=-5V;
so I have:
[Pullup Reference] 5.0 NA NA
[Pulldown Reference] -5.0 NA NA
To extract Pulldown and Pullup curves
have I to consider the Voltage sweep from - (vcc - vss ) to 2* (vcc -
vss ) ?
so from -10 V to 20 V ?
is this correct? Is not a too wide range?
Regards,
Fabio
