DDR4 clock (MCK) termination

[trondwang]

Hi NXP, in the reference design LS1043ARDB-PA/PB the termination resistor (R470 and R468) is 36 ohm for the differential clock.

The termination resistor for the single ended signals of the address bus/control  (R186+..) is 39 ohm.

Why do you use a lower resistance value for the differential signal.than for the adress bus/ control bus?

regards Trond Inge Wang

[ufedor]

The termination circuit was simulated and optimized for the specific layout using HyperLynx.

Similar method is recommended for new designs.