i.MX ProcessorsのトピックRelaxing LPDDR4 timings for high temperature

Relaxing LPDDR4 timings for high temperature

frank_vanhooft — Fri, 08 Jul 2022 21:10:02 GMT

We're using an iMX8-mini with a single LPDDR4 x32 device. We're working on qualifying second and third source LPDDR4 chips, and having a little difficulty with some parts when running memtester at high temperature (75 C ambient or higher). We're using industrial-temp or automotive-temp parts rated for 1600 speed grade. We run the imx8 DDR interface at 1500 (as configured in the RPA spreadsheet). At high temps we still see the occasional memtester error with certain RAM chips.

In the RPA spreadsheet, I've selected "option 2" for the LPDDR4 MR4 manual de-rate workaround.

I'm looking for suggestions regarding which parameters I might change in the RPA spreadsheet to accommodate looser timings for the RAM, to help it at the higher temperatures.

Thanks.

Re: Relaxing LPDDR4 timings for high temperature

Rita_Wang — Thu, 14 Jul 2022 08:05:43 GMT

How about the temperature range of the DDR you are using?

Re: Relaxing LPDDR4 timings for high temperature

frank_vanhooft — Thu, 14 Jul 2022 14:34:18 GMT

-40 to +105C

Alliance AS4C256M32MD4-062BAN

Re: Relaxing LPDDR4 timings for high temperature

Rita_Wang — Tue, 19 Jul 2022 09:19:33 GMT

At high temps we still see the occasional memtester error with certain RAM chips.

Could you share the full log to us?

Re: Relaxing LPDDR4 timings for high temperature

frank_vanhooft — Tue, 19 Jul 2022 22:40:13 GMT

I'm going to close this. I contacted an NXP guru, who pointed me to this:

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/iMX-8M-Mini-Register-Programming-Aid-DRAM-PLL-setting/ta-p/1112094

That gave us the pointers we needed to move forward. We have the part working at high temps now. Thanks.