2.4 Constraints and limitations of use
The constraints and limitations of the DMC-620 depend on the SDRAMs used, and the interoperability within the PHYs. This, in turn, depends on the DDR Physical Interface (DFI) parameters.
The SDRAMs supported by the DMC-620 are:
- Double Data Rate 3 (DDR3) SDRAM.
- Low-voltage DDR3 SDRAM.
- Double Data Rate 4 (DDR4) SDRAM.
Note: These devices are described in the JEDEC specifications that are global
standards for the microelectronics industry.
The DIMMs supported by the DMC-620 are:
- DDR3 UDIMM.
- DDR4 UDIMM.
- DDR4 RDIMM.
- DDR4 LRDIMM.
- DDR4 3DS. DIMMs utilizing 3DS parts are supported.
The JEDEC specification implies the following constraints and must be met:
- t_xp < t_xsr - Exiting power down timing must be less than
- t_mrw_cs < t_mrw - The delay after a Mode Register Write command and
before any other command is issued to a different rank less than the delay applied
after a Mode Register Write command and before any other command is issued to the