11.1.6.3.2 DDR Voltage Reference

The DDR_VREF input must be driven at all times by a voltage source equal to VDDIODDR/2. See below the recommended schematics to drive DDR_VREF.

Figure 11-11. DDR_VREF Recommended Schematic with DDR2/3(L)-SDRAM
Figure 11-12. DDR_VREF Recommended Schematic with LPDDR2/3-SDRAM