AM335x: Peripheral devices power sequence

Chris Zhao1

Other Parts Discussed in Thread: AM3352

Hi experts,

I'm designing my work with AM3352, there are many device controlled by it. I attached a diagram below. My question is about the power sequence about these parts.

1) For now, all peripheral devices except DDR3L SDRAM are powered on firstly, then power management controller will power on AM3352 and DDR3L SDRAM, is there any problem it?

2) Do you have any recommendation about this case?

Thanks

Chris

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

Chris Zhao1 said:
1) For now, all peripheral devices except DDR3L SDRAM are powered on firstly, then power management controller will power on AM3352 and DDR3L SDRAM, is there any problem it?

This is totally wrong and may lead to AM335x device damage. AM335x I/O pins are NOT fail-safe. See parameter "Steady state max voltage at all IO pins" in section 5.1 from the AM335x Datasheet Rev. J. Also check Note 8 below the table.

Chris Zhao1 said:
2) Do you have any recommendation about this case?

You can refer to the AM335x reference designs: http://processors.wiki.ti.com/index.php/AM335x_Boards and http://elinux.org/Beagleboard:BeagleBoneBlack#Hardware_Files

0 Chris Zhao1 over 9 years ago in reply to Biser Gatchev-XID

Expert 1240 points

Biser,

Thank you, this is very important for my design.

There are three main control device, including a FPGA, another small processor and AM3352. Meanwhile there are many connections and interface between them. Is that mean AM3352 must be powered on firstly?

Thanks
Chris

0 Biser Gatchev-XID over 9 years ago in reply to Chris Zhao1

TI__Guru**** 393215 points

Yes, either AM335x power supplies must ramp-up first, or peripheral power supplies must ramp-up together with AM335x power supplies in such a way that the above parameter for AM335x I/O pins is met.

0 Chris Zhao1 over 9 years ago in reply to Biser Gatchev-XID

Expert 1240 points

Got it, have a good day.

Chris

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AM335x: Peripheral devices power sequence