Re: Driver Output Impedance Calculation

Paul Gregory wrote:
>
> Hello ibis users,
>
> I need some help in understanding how to determine output
> impedance.
>
> Given the ibis model data that follows, how does one determine
> the output impedance of this driver for both the pullup and
> pulldown side of the driver.
>
> Thanks for your help.
>
> -- Paul Gregory
>

For a first order approximation, I would do the following:

        ignore the clamp diodes,

        look at the pulldown curve data, pick 5 voltage points within the
        voltage swing of the signal, apply Ohms law to calculate the impedance,
        then average the values.

        do the same for the pullup curve but remember that the voltage is
relative
        to ground so you need to subtract from VCC to determine the voltage
        across the pullup.
        

-- 
N. Paul Taddonio   phone: 508-250-1920 x245    fax: 508-250-0036
SKY Computers, Inc.
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