RE: PCI bus 3.3V to 5V addapter card

[Andrew Ingraham <Andrew.Ingraham@digital.com>]

Franklin Koppen asked:

>I have a Silicon Graphics 320 Visual Workstation with a PCI bus that
>supports only 3.3 V
>Do you know if there are DC/DC convertor PCI-cards in the market that
>will take the 3.3 V from the PCI bus,transform it to 5V, put the 5V on
>the appropriate
>5V pins of the PCI bus?

Even the SGI workstation surely has 5V *power* on the appropriate 5V
power pins.  It is mandatory.

I think what you are looking for is something to change the signal
switching levels.  That is more complicated, it can't be done with a
simple voltage converter.  It generally takes a PCI-PCI bridge, extra
mechanical considerations, etc.  Some parts don't work with PCI-PCI
bridges.

Are you aware that many PCI adapter cards on the market are "Universal"
and can be plugged into PCI connectors that use either 3.3V or 5V
signaling?


>Are the PCI-bus connectors "keyed" for 3.3V and 5V cards or is this not
>controlled in the PCI-specs?

Yes, they are keyed, according to the specs.  "Universal" PCI cards have
both key cutouts so they can be plugged into either connector.

Regards,
Andy