ESP32-WROVER temperature specification change

[Grant.Bradley]

I notice that on the latest datasheet the max operating temperature on the WROVER has been changed from +85deg C to +65deg C. Can you please explain why? Note. the WROOM is still +85deg C and the PSRAM is rated to +85deg C to the best of my knowledge.

My product needs to operate at an ambient of +55deg. C and I have about 17deg C gradient between top surface of WROVER and ambient outside of my housing. (i.e. 72 deg C on top surface of WROVER when at 55 deg C ambient)

Will using the thermal pad under the device help if the reason for changing the spec down to +65deg C is due to hot spots within the module? or any other reason? or suggestions?

[loboris]

It is also mentioned that

ESP32-WROVER with high temperature range option is available for custom order.

What exactly is different (componnents, testing, ...) on the custom ordered module with higher operating temperature (which is ...?) ?
The maximum operating temperature of +65 deg C is quite unusual (low) and could indicate some module design flaw.

Changing the specifications without the explanation is really a bad practice and in this case the change is certainly not an insignificant one.

[ESP_Sprite]

Let me look into this.

[Grant.Bradley]

This change in specification has stumped us now as we are about to comit to expensive EMC testing and then build a first run of production boards in the next few weeks. I need an answer urgently!
I need to understand what my options are. i.e. Continue with the current design understanding the limitations s.t. we can make an informed decision, or order the higher temp spec part and hope that the costing is still very similar, or to change the design to using a WROOM with external SRAM (not an option I really want to entertain!)

[ESP_Sprite]

Gotcha. I asked around, and for now it seems the issue here is mostly that the part we used to use for the Wrover isn't made anymore (I assume, not sure, something something supply issues), so we had to switch to 8MiB parts. Unfortunately, these parts need to be verified to work at 85C, and we have had some issues that made us go 'Hmm' with some of the chips. We're still testing them, but in order to stop people from using them for high-temp things, the datasheet was modified. I'm still asking around for more details. If you want to know your options wrt the high-temp-certified parts, feel free to poke sales at espressif dot com, they may not even be that more expensive than the normal parts.

[WiFive]

So...

1. It only affects 64mbit psram parts
2. Even though the lyontek and espressif 64mbit psram are spec'ed to 85c they have presented issues above 65c

?

Is this true for both 1.8v and 3.3v parts? At 40mhz?

[ESP_Sprite]

I can't tell exactly, tests are still underway.

[Grant.Bradley]

When do you expect feedback on this? When do you expect the tests to be completed?

[ESP_Sprite]

Not until next week at least; this week is a holiday here in China.

[Grant.Bradley]

Any feedback on this yet?