Re[1]: V/I table in Bench measurements

Hello Bob, Syed:

     You know, Syed's question brings up an interesting point. Suppose the
     VCC of a device is at +5V but the output is TTL and the maximum swing
     is, say 3.5V. Should the output be characterises from -3.5 to 7.0v
     (the maximum voltage range that the output would ever realistically see)
     or does one still have to do the -5 to +10v range?

                  Best Regards,
                  Stephen Peters
                  Intel Corp.

Syed:

Here are my views on your questions:

(1) The Voltage table can be presented in any order: -ve to +ve or +ve to -ve.
(2) The table itself must go to at least the specified limits. It is
permissible to do the measurements over a reasonable range and then extrapolate
to the end points. For example, you man not want to measure below -2V, but you
still need to provide at least one extrapolated data point out to -5V if Vcc
is 5V.

Bob Ross,
Interconnectix, Inc.

> Hi fellow gurus:

> Got two questions about the V/I table.

> 1) Does the Voltage table need to ramp down from a -ve number to a +ve or can it
> be from +ve to -ve number as well ?
> Ex: For [Pulldown] the Voltage table goes from -5.0V to +10.0V

> 2) For most of the V/I table, IBIS shows that the voltage range should go from
> +10V to -5V. Problem is, there are devices whose I/O structure cannot handle
> swings that large. In that case, since we should not test a device beyond
> it's Absolute Recommended Operating(ABS Max) range, is it O.K NOT to swing
> the I/O all the way to +10 to -5V ???

> Regards,
> Syed huq
> National Semiconductor
Received on Wed Jul 20 15:47:33 1994