[IBIS] More Details about Vinh+, Vinh-, Vinl+, Vinl-

Hello Experts,

I referred some of the IBIS documents regarding the explanation for Vinh+, 
Vinh-, Vinl+, Vinl-.
But what I got was,

| Vinh+                         Hysteresis threshold high max Vt+
| Vinh-                         Hysteresis threshold high min Vt+
| Vinl+                 Hysteresis threshold low max Vt-
| Vinl-                  Hysteresis threshold low min Vt-

From the cookbook I came to know that "these parameters are used for 
defining two thresholds for the rising edges and
two thresholds for falling edges ".

        But I didn't understand what "2 thresholds " mean. Is it something 
related to PVT variations (Vinh at fast corner and Vinh at slow corner )?

Please let  me know the exact meaning of these parameters as soon as 
possible.

Thanks !

Best Regards,

Sudarshan HN
CTO /Process & Library Technology
NXP Semiconductors
Banglore-08
Ph:080-25579000  Extn:1586
seri:sudarsha@inpsblr
E-mail: sudarshan.honnudike@philips.com
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