AM335x VDDSHVx and VDDS_RTC

Hi  Matsuzaki-san,

There are strict requirements for power-up sequencing. Please check section 6.1 of the AM335X Datasheet Rev. G. If these requirements are not observed this may cause permanent damage to the device.

Hi Biser-san,

I'm sorry for not following the power-up sequencing.
Actuary, my customer's board does not power-up even thogh using TPS65910A31.
We are checking some doubtful points on the board.
Adding 3.3V to VDDSHVx and 0.9V appers from VDDS_RTC is one of the point.
Maybe there is short circuit between VDDSHVx and VDDS_RTC out of AM335x,
but is it possible to show some information about internal power rail(VDDSHVx and VDDS_RTC) ?

Regards,
Takeshi Matsuzaki

What you are seeing are probably internal leakages. I emphasize again that VDDS_RTC must ramp-up before all other power supplies. If you continue this approach of investigation you will probably damage the processor, if that has not happened already.

Hi Biser

OK, I will stop this approach, sorry for embarrasing you.
Is it possible to show some information about internal power rail(VDDSHVx and VDDS_RTC) ?

Regards,
Takeshi Matsuzaki

Sorry, I don't have information about internal structure of the power rails.

Biser,

Is it possible to ask your design team ?

Regrds,
Takeshi Matsuzaki

There is no way to discuss such information on a public forum, or even outside TI.