Spec issue on MSE leakage current in SPI-3

Bill Galloway BillG at breatech.com
Thu Apr 29 14:44:39 PDT 1999


* From the T10 Reflector (t10 at symbios.com), posted by:
* "Bill Galloway" <BillG at breatech.com>
*
John,

In general I agree that the receiver will not care if you clamp the line at
3 volts. How hard would you clamp it??? I have seen some older designs that
could put out allot of current above 3 volts.  Would 100ma damage you?? Would
100ma continuos damage the driver??? How would the impedance discontinuity of
your clamping effect signal integrity, reflections, etc.???

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

-----Original Message-----
From: John Lohmeyer [mailto:lohmeyer at ix.netcom.com]
Sent: Thursday, April 29, 1999 4:34 PM
To: BillG at breatech.com; T10 Reflector
Subject: RE: Spec issue on MSE leakage current in SPI-3


I do not want to outlaw old devices.  I just want to make it legal for new
devices to exist on the same bus.  If my new device tends to clamp signals
at 3 volts (or a little higher) when an old device trys to drive it higher,
where is the harm?  The receivers will still see a valid high-level
(assuming SE) and we should not see such high voltages on LVD.

The 20 uA leakage spec at 4.1V will add a lot of cost and complexity for no
benefit.

John

--
John Lohmeyer                  Email: lohmeyer at ix.netcom.com
LSI Logic Corp.                Voice: +1-719-533-7560
4420 ArrowsWest Dr.              Fax: +1-719-533-7036
Colo Spgs, CO 80907              BBS: +1-719-533-7950

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