Specifications

Intel

810E2 Chipset Platform

156 Design Guide

6.5. Power_Supply PS_ON Considerations

If a pulse on SLP_S3# or SLP_S5# is short enough (~ 10-100mS) such that PS_ON is driven active

during the exponential decay of the power rails, a few power supplies may not be designed to handle this

short pulse condition. In this case, the power supply will not respond to this event and never power back

up. These power supplies would need to be unplugged and re-plugged to bring the system back up.

Power supplies not designed to handle this condition must have their power rails decay to a certain

voltage level before they can properly respond to PS_ON. This level varies with affected power supply.

The ATX spec does not specify a minimum pulse width on PS_ON de-assertion, which means power

supplies must be able to handle any pulse width. This issue can affect any power supply (beyond ATX)

with similar PS_ON circuitry. Due to variance in the decay of the core power rails per platform, a single

board or chipset silicon fix would be non-deterministic (may not solve the issue in all cases).

The platform designer must ensure that the power supply used with the platform is not affected by this

issue.