Refer to the PDF data sheet for device specific package drawings
DDR_VREF is used as a reference by the input buffers of the DDR3 memories as well as the device. DDR_VREF is intended to be half the DDR3 power supply voltage and is typically generated with a voltage divider connected to the VDDS_DDR power supply. It should be routed as a nominal 20-mil wide trace with 0.1 µF bypass capacitors near each device connection. Narrowing of DDR_VREF is allowed to accommodate routing congestion.