PF3001 with IMX6 solo

[Fred_Jutras]

Hi, 

I am having some issue with a PF3001 powering an IMX6 solo. This problem is very rare but I would like to find the cause and fix it. Basically, sometime, the unit is not booting properly. I have read quite a bit of community question about the same problem but I haven't find a way to fix the issue I have. 

It seem that the RTC_CLK on the IMX6 is not up fast enough sometime and this cause the unit not to boot. I looked at the POR_B on the PF3001 (or RESETBMCU) and it does go up a bit too fast. I looked into the data sheet to see if we could assert that pin directly but it doesn't seem so. I also try to use a delay with a RC on the PWRON but it was not enough (1M + 0.1µF on PWRON using VSNVS). 

If someone could give a hint on where to look or how to delay the supplies, I would appreciate. 

Thanks,

Fred

[guoweisun · Accepted solution]

What's your desired rise up time of PRO_B pin?

[Fred_Jutras]

Hi Guoweisun, 

I don't particulary need a set time, at the moment, it seem that the unit goes up as soon as possible which from the time the 5V is up until the POR_B de-assert, is approximatively 16 msec. From the errata ERR009678: 

"3. Delay POR_B de-assertion until after the 32 kHz crystal is stable (approximately 300 ms to 500
ms from VDD_SNVS_IN ramp timing; this timing is dependent on the crystal start up timing
characteristics)."

I don't think I would need that long of a delay but anything might help. Maybe I would need to search for a different crystal too. 

Thanks

Fred