Available options in dual channel topology:
- Dual Channel 16-bit
- Dual Channel 24-bit as 16-bit Data with 8-bit ECC
- Dual Channel 32-bit
PCB Expansion Options:
All Dual Channel DDR4 Component interfaces will always have the Optimum option. This is because all configurations follow the same basic pinout while more Nibbles are used as the data widths get larger. The Dual Channel DDR4 Component pinouts are not compatible with Single Channel DDR4 Component pinouts because of the differences in the input reference clock Nibble and the Command/Address/Control (CAC) Nibbles. The CAC Nibbles for Dual Channel interfaces map to Data Nibbles for Single Channel interfaces so there is no way for one hardware design to satisfy the needs for both types of topologies. In addition, Dual Channel topologies only support a single DDR4 interface clock output since any supported configuration will be within the DDP Deep loading guidelines. The default Optimum pinout will automatically support DDP Deep rank expansion or 3DS device support. There is no support for DDP Deep 3DS Single Channel or Dual Channel component interfaces. DDP Deep 3DS components are supported in RDIMM/LRDIMM applications.
The Dual Channel DDR4 Component interface pinouts optimally pack the Triplet by placing the utilized Nibbles starting first in the Left bank and expanding to the Right bank as the data width gets larger. The figure below shows the Dual Channel 16-bit bank packing with the unused Nibbles on the Right side of the bank.