Subject: RE: [IBIS] About Vmeas
From: Ingraham, Andrew (Andrew.Ingraham@hp.com)
Date: Tue Apr 08 2003 - 07:07:20 PDT
Typically, Vmeas is somewhere in the middle of the waveform. You should get its value directly from the device's data sheet.
On many data sheets, you will see timing diagrams showing input and output signals. Quantities such as tPLH, tPHL, etc. are indicated, and are specified at specific voltages. For TTL, and CMOS devices that use TTL levels, this voltage is usually 1.5V. For some CMOS it may be 50% of VDD.
Andy
> Recently, I was asked to add the Vmeas parameter to an ibis model i'm
> running.
> It's definition is not clear at the ibis spec.
> [ Reference voltage for timing measurements ] .
> Is it the total output voltage the signal should climb to
> or just a part of it?
>
> Thanks ahead for your responses
>
> Lior Aviv,
> Motorola Semiconductor Israel.
>
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