What is the recommended power supply sequencing method? What happens if I do not follow this method?
Power sequencing and ramp-up requirements for Virtex-II/ Virtex-II Pro are documented in the Virtex-II/Virtex-II Pro Data Sheet -> DC and Switching Characteristics (Module 3) -> Power-On Power Supply Requirements:
1. For Virtex-II ES only, do not hold any power supply at 0 VDC while ramping up the other.
2. For Virtex-II, the "Power-On Power Supply Requirements" section states that each bank draws up to 300 mA when VCCO powers up before VCCAUX. The ICCO minimum remains at 10 mA/device (1.25 mA /bank) for power on. The 300 mA per bank can occur if VCCO is up in the absence of VCCAUX AND if the power supply can supply the current. (These conditions include power on, a glitch on VCCAUX, or hot swap). If the power supply cannot supply the current, you will not see the current. The 300 mA transient current eventually disappears, even if VCCAUX does not power up. This issue does not apply to Virtex-II Pro.