AM3352: DDR3 memory timing tuning over temperature

Munan Xu

Part Number: AM3352

Hello,

I have a customer who's experiencing DDR failures on some of their prototype devices with the AM3352. Although not all devices will crash, some will after the customer application has been running a while which indicates some issues with heating. The customer has also been able to specifically heat the DDR chip with a heat gun and cause devices to fail.

Customer is using the ISSI IS43TR16256A-125KBL DDR3 SDRAM.

I have attached the DDR worksheet for the AM335x that the customer has filled out, any feedback on any parameters that could be improved woud be great!

Thanks,

MunanAM335x_DDR_register_calc_tool_400MHz.xls

over 6 years ago

0 Biser Gatchev-XID over 6 years ago

TI__Guru**** 393215 points

Hi Munan,

I have asked the DDR experts to comment on this. My personal opinion is that using a heat gun is not the correct method to perform temperature tests. A thermal chamber with precisely controlled temperature should be used, as described here: processors.wiki.ti.com/.../AM335x_Thermal_Considerations

0 Munan Xu over 6 years ago in reply to Biser Gatchev-XID

TI__Expert 4610 points

Hi Biser,

Agree that a thermal chamber is better, but the point is that failure happens over time in regular operating conditions as well (room temp ambient), and customer could accelerate that failure by increasing the heat on the DDR section.

Thanks,

Munan

0 JJD over 6 years ago in reply to Munan Xu

TI__Guru* 80310 points

Munan, a couple of questions.

1. Did they run the software leveling algorithm on their board found here: processors.wiki.ti.com/.../AM335x_DDR_PHY_register_configuration_for_DDR3_using_Software_Leveling ?

2. Typically, DDR3s operating above 85C will require a faster refresh rate. Is the memory possibly heating up beyond 85C?

Regards,
James

0 JJD over 6 years ago in reply to JJD

TI__Guru* 80310 points

I also noticed they rounded up on some of the parameters in the spreadsheet (which is fine), but they rounded down on tRC, which would pose a problem. They need to either input the exact parameter from the datasheet, or round up for all of them except tRASmax. tRC should be at least 50.625ns

Regards,
James

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AM3352: DDR3 memory timing tuning over temperature