Virtex "Virtual VCC"

Hi !

I have a PCI Mezzanine Card (PMC) with a Virtex 400 and a front panel connector. The Virtex is connected to the SCSI-2 style front panel connector with 68 pins.These pins are interleaved signal and ground pairs.So, I have 34 free I/O at the front panel connector. I would like to connect a little add-on board to this front panel connector. This board will be populated with a Gigabit Ethernet Controller (PMC-Sierra PM3387). Besides data and control signals I have to provide power to the add-on board.

I am planning to connect the add-on board VCC plane with the I/O pins at the front panel connector. Then the Virtex will drive '1' at the front panel connector I/O. The add-on board ground plane will be connected with the ground pins at the front panel connector.

Can this provide sufficient power to the add-on board ? Is there a better way to provide power ?

Thanks in advance.

Mark Lenz

Reply to
lenz
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Mark, your question cannot be answered without knowing the Icc consumption of that extra board. If it is

Reply to
Peter Alfke

Hi Peter,

thank you for your response.

The datasheet of the chip which is on the add-on board states a DC Input Current of +/- 20mA. I have a total of 4 pins to provide power to the add-on board. The Virtex datsheet states a output current for one pin of +/- 24mA for LVTTL. As a novice I would expect that one pin with +/- 24mA would be sufficient to source the add-on board which requires +/- 20mA. Is this correct ?

How can I determine the value of the experiment resistor. I assume Vcc/Icc. Is this correct ?

Regards, Mark Lenz

Reply to
lenz

Reply to
Peter Alfke

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