i.MX 8M Plus LPDDR4 question

[Andras_Magyar]

Dear Experts,

We designed a board recently with i.MX 8M Plus (pn: MIMX8ML8CVNKZAB).

We probably used an LPDDR4x memory (PN: MT53E1G32D2FW-046 AAT:C) which we found out later unfortunately since the memory test tool of the NXP failed (CA training failed command address). We already know that LPDDR4x is not supported by the 8M Plus family so for the second prototype we want to change it to an LPDDR4 which is not easy to find at least at Micron since they get easily obsolete after time and the other problem is that based on the Micron's datasheets it is not easy to decide if a memory is LPDDR4 or LPDDR4x.

My question is can you please tell me that the old memory really is LPDDR4x (PN: MT53E1G32D2FW-046 AAT:C) and other question is which LPDDR4 memory do you suggest to use with imx8mplus processor that is 100% compatible and has 32Gb or 64Gb capacity?

We want to know how to decide if a memory is LPDDR4 or LPDDR4x for sure.

We could only judge is by the first indicating VDDQ voltage which has to be 1.1V for LPDDR4 and 0.6V for LPDDR4x.

We also checked the eval board of, here:
https://www.nxp.com/design/design-center/development-boards-and-designs/8MPLUSLPD4-EVK

But according to many sources it is obsolete already:

https://www.newark.com/micron/mt53e1536m32d4dt-046-wt-a/dram-48gbit-2-133ghz-vfbga-200/dp/80AH8335

https://eu.mouser.com/ProductDetail/Micron/MT53E1536M32D4DT-046-WTA?qs=0lSvoLzn4L%252BcP9ucpjUetw%3D...

We want to know what is the truth about it and also if other vendors like ISSI could be good.

Please if possible provide us specific part number.

I am waiting for you kind reply.

Best Regards,

Andras

[Andras_Magyar]

Dear Jorge,

We checked the page!

There are two validated memories for imx8plus:

1. MT53E1536M32D4DT-046 WT:A -> this is already obsolete (would be good because EVK uses this one).
2. MT53E2G32D4DE-046 AUT:C -> here we have the datasheet please check below:

https://4donline.ihs.com/images/VipMasterIC/IC/MICT/MICT-S-A0020191269/MICT-S-A0020191269-1.pdf?hkey...

I believe that also this one is validated but in the datasheet as you see there is not clear indication as how to decide that a memory is LPDDR4 or LPDDR4x or better which mode is the default for these memories.

What we want to do at bring up is that we want to use the NXP tool memory tester and once it finishes with the tuning we want to put bootloader and Linux on the processor.

The datasheet also mentions the following at the beginning:

"When using the product as an LPDDR4
device, refer to LPDDR4 setting section LPDDR4 1.10V
VDDQ at the end of this data sheet."

For this there is a procedure but I assume that the processor cannot do it because of the initial VDDQ=0.6V.

So the questions are:

1. MT53E2G32D4DE-046 AUT:C is 8GByte but only this size is supported or we can choose also a 4 GByte version of it (PN in the datasheet: MT53E1G32D2FW-046 AUT:C) ?

2. How to decide based on the Micron datasheet that a memory is supported (LPDDR4 with VDDQ=1.1V by default)?

3. Only dual rank dual channel is supported ?

Because in the first table you indicate for imx8plus: "Assumed memory organization
dual rank, dual-channel  device with 17-row addresses (R0-R16)"

Best Regards,

Andras

[JorgeCas]

Hello,

1. No, you can select other densities and the maximum density is 64Gb/8GB.

2. You need con confirm that operation with manufacturer, this working voltage between LPDRR4 and LPDDR4x should be defined by voltage level power supply.

3. Single rank and dual rank are supported.

Best regards.

[Andras_Magyar]

Hi Jorge,

I still feel that my question is unanswered because since you designed an EVK for iMX8 Plus so you had to know if the used LPDDR4 is compatible with the processor or not.
Based on this I assume that there is someone at NXP who could tell precisely which Micron memory is compatible with iMX8 and also how to decide it based on the part number, device code or anything else.
Your EVK was designed by your colleague Frank Liu.
Could you ask him about this?

Unfortunately Micron is not responsive for a while so I'd very much appreciate your help since these board are not cheap to manufacturer and assemble so we do not want to make any unwanted mistake.

Thank you for you understanding.

Regards,
Andras

[JorgeCas]

Hello,

The validated memories are described in the post I sent before, it is a fact that will work with the processor, the part numbers you mentioned at first are compatible LPDDR4 devices for i.MX8MP.

If you are having issues with stress test, there are some points that could cause this issue such as: signal integrity, layout, initialization and timing scripts.

Best regards.

[JorgeCas]

Hello,

i.MX8MP is not compatible with LPDDR4x devices, as you mention, a good method to identify LPDDR4/x is checking the working voltage.

Here our DDR compatibility list for i.MX8M devices.

i.MX 8M Quad/8M Mini/8M Nano/8M Plus - LPDDR4, DDR4 and DDR3L memory compatibility guide - NXP Commu...

Best regards.