How should the CKE signal be terminated for DDR3 and DDR4 interfaces?

Description

The CKE signal is pulled down to GND on the DDR3 HiLo daughter card and terminated with a Thevenin parallel termination on the DDR4 HiLo daughter card.

Resolution

All address and command signals, including the CKE signal, should use a fly-by termination for Arria®10 and Stratix®10 DDR3 and DDR4 interfaces.

These signals should be terminated with a resistor to VTT at the end of the fly-by topology. This termination is required only for discrete memory device implementations and is not required for DIMMs.