[NCG][MIC-6315] on board DDR4 ( Samsung ) DDR_VREF Voltage problem.

[BLan]

MIC-6315 DDR4 Circuit diagram, The DDR_VREFCAB reference voltage ripple is too large (R204 and R206 DDR_VREFCAB ripple 30~50mV), so I use U137 pin6 (output VTTREF) when DDR_VREFCAB reference voltage, I want to ask, I use TPS51200 PIN 6 when DDR_VREFCAB reference voltage Is it feasible?

[CarlosAM_INTEL]

​Hello, @BLan​:

Thank you for contacting Intel Embedded Community.

In order to be on the same page, could you please let us know if design related to this thread has been developed by you or a third-party company? In case that it is a third-party device please give us the name of the manufacturer, the part number, model and where is stated the information related to it. On the other hand, if it is your design, could you please let us know the part number and SKU of the processor and chipset related to it?

Waiting for the information that may answer these questions.

Best regards, 

@Mæcenas_INTEL​. 

[BLan]

ntel® Xeon® Processor D-1539 (12M Cache, 1.60 GHz) - Broadwell-DE

The DDR_VREFCAB reference voltage : TPS51200 (TI)

[BLan]

MIC-6315 DDR4 Circuit diagram, The DDR_VREFCAB reference voltage ripple is too large (R204 and R206 DDR_VREFCAB ripple 30~50mV), so I use U137 pin6 (output VTTREF) when DDR_VREFCAB reference voltage, I want to ask, I use TPS51200 PIN 6 when DDR_VREFCAB reference voltage Is it feasible?

[BLan]

Is there an updated message?

[CarlosAM_INTEL]

​Hello, @BLan​:

Thanks for your updates.

We have received the provided information. We are checking our sources to find the information that may help you. As soon as we have it, we will let you know.

Thanks in advance for your patience and understanding.

Best regards,

@Mæcenas_INTEL​. 

[BLan]

Is there a new message?

[CarlosAM_INTEL]

​Hello, @BLan​:

Thanks for your replies.

Could you please verify if this inconvenience can be reproduced with any of the memory listed in the following website?

https://www.intel.com/content/dam/www/public/us/en/documents/platform-memory/ddr4-2133-sodimm-ecc-validation-results.pdf

It is important to let you know that the use of TPS51200 REFOUT is feasible, but note that VREFCA is supplied by the SoC by the DDR_VREF signal and is filtered by low pass filter near the DIMMs.

In some CRBs the DIMM's VREFCA and CPU pin CR52 DDR_VREF are using the reference from resistor divider down from the VDDQ instead of the VTT LDO TPS51200 REFOUT (pin 6).

We hope that this information may help you.

Best regards,

@Mæcenas_INTEL​.