Spec issue on MSE leakage current in SPI-3

Bill Galloway BillG at breatech.com
Thu Apr 29 13:51:47 PDT 1999

* From the T10 Reflector (t10 at symbios.com), posted by:
* "Bill Galloway" <BillG at breatech.com>
>I don't know where 4.1V came from but it is obviously higher than the
>3.63V which any 3.3V device could possibly expect to generate on the bus.
>Besides, if LVD devices are current mode devices, why are we concerned
>about the bus being driven to levels that are HIGHER than the Vdd of the
>driving devices?


What your Vdd happens to be is not important.  If a bus supports multiple
vendors and or multiple generations of devices the only thing that matters is
the highest voltage of any device on the bus. There are 5V devices still in
common use today.  I do understand the design problems that this causes for the
silicon but one major benefit of SCSI is the simultaneous support of multiple
device generations.  Maybe someday we can outlaw old devices on new busses but
for now I do not see how.

Bill Galloway
BREA Technologies, Inc.
P: (281) 530-3063
F: (281) 988-0358
BillG at breatech.com

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