Why is a floating voltage observed on the 2.5V VCCIO rail during power-up of Cyclone IV GX, Cyclone V, Arria V, Stratix IV or Stratix V devices?

Description

If a 2.5V VCCIO power rail is shared with VCCH_GXB in Cyclone® IV GX or Cyclone V devices, or VCC_AUX in Arria® V,  Cyclone V, Stratix® IV or Stratix V devices, a floating voltage may appear on the 2.5V VCCIO rail.

For further details about floating voltages on VCCH_GXB and VCC_AUX, refer to the related solutions.

Related Articles

• Is there any problem if a floating voltage exists on VCCH_GXB before it is ramped in Cyclone V devices?
• Is there a problem if a floating voltage exists on VCC_AUX before it is ramped in Arria V, Cyclone V, Stratix IV, and Stratix V devices?
• Are there any problems if a floating voltage exists on the VCCH_GXB supply rail before it is ramped in Cyclone IV GX devices?