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RE: universal pci card into a pci-x slot

Andy & Victor,

I think that the System Board Specification (PCI 2.3 section 4.3) gives the
requirements of the power rails, independant of the signaling levels.
Section says "all PCI connectors require four power rails: +5V,
+3.3V, +12V and -12V" and gives table 4-10 which lists the tolerances of the
3.3V and 5V power rails as 3.3V +- 0.3V and 5V +- 5%. 
PCI-X 1.0b says "Device and add-in card power supply voltages and tolerances
and add-in card load limits are the same as for conventional PCI devices and
add-in cards. ". For PCI-X 2.0 it is in section 2.5.1 of the Electrical and
Mechanical Addendum.


Tony Clark

> -----Original Message-----
> From: Ingraham, Andrew [mailto:Andrew.Ingraham@hp.com]
> Sent: Tuesday, January 14, 2003 4:07 PM
> To: Victor Piron
> Cc: pci-sig@znyx.com
> Subject: RE: universal pci card into a pci-x slot
> > What are the Power Supply Tolerances (for 5 V and 3.3V) for a Pci-x
> > slot?
> It is the same as for PCI: 3.0 - 3.6V.
> The 5V supply voltage must be provided, but technically there is no
> tolerance specification for it, because PCI-X doesn't use 5V 
> signaling.
> The only place in either spec where the supply voltage tolerances are
> given, is in the DC Specifications for 5V Signaling (PCI 
> only), or 3.3V
> Signaling (PCI or PCI-X).  4.75 - 5.25V is most widely used.
> Regards,
> Andy