IMX8 Plus LPDDR4 CKE Pulldowns and CK termination

[nithinmike]

Hello,

The IMX8 Plus EVK has unpopulated 10k pulldowns on LPDRR4 CKE inputs. What is the purpose of these pulldowns? Do they need to be populated for any reason?

There are also unpopulated 150 ohm termination resistors on the LPDDR4 clock signals. Do these ever need to be populated? Is the EVK using on die termination for the clock signal?

[JorgeCas]

Hello,

Those DNP resistors were used for testing.

DNP CKE pulldown resistors were used to secure low logic states. CKE HIGH activates and CKE LOW deactivates the internal clock signals, input buffers, and output drivers.

DNP 150-ohm resistors were used to match the characteristic impedance of differential pair, which helps with signal integrity.

It is not necessary to populate these resistors and yes, the EVK is using die termination for clock signal.

I hope this information helps you.

Best regards.