STE10/100A - Reference Design NIC Schematic |
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Do you have the ORCAD files for the reference design for this device?
Yes, the ORCAD file is available for the STE10/100A reference design NIC card. Please contact your ST Sales Rep for further information. |
| 2 |
On the STE10/100A reference design NIC schematics, there are two optional connections for the PME pin. One is a straightforward connection the other uses an NPN transistor and a couple of resistors. Explain when to use what.
In the majority of all applications, the direct connection to PME will work fine. However, there are some motherboards that during power-up may generate glitches on PME that still could cause problems to the PME of the STE10/100A. So in cases where the STE10/100A is embedded in a system where the power-up conditions of the PCI bus are known, the PME connection to the STE10/100A can be direct. In applications where the STE10/100A may be used in a wide variety of undetermined PCI busses (such as an adapter card). It is suggested that the NPN transistor plus 2-resistor solution still be used. Basically all this solution does is just isolate the PME pin until Vdd has fully powered up. |
| 3 |
On the STE10/100A reference design NIC schematics, what are resistors R28, R30 and R34 for?
Resistors R28, R30 and R34 comprise a termination of the unused pairs of the CAT 5 cable. This termination basically looks like a 100-ohm load, matched to the line, which is by passed to chassis ground. This termination is added for robustness and noise reduction. |
| 4 |
What is the purpose of the resistors R32/R33?
The 75 Ohms resistors R32/R33 are for line termination. |
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