topic Re: i.MX502 & MC34709 Power-down sequence in i.MX Processors

i.MX502 & MC34709 Power-down sequence

norishinozaki — Mon, 23 Feb 2015 06:08:42 GMT

Hello,

I'd like to use MC34709 PMIC along with i.MX502.

i.MX502 requires the power-off sequence in the reverse of the power-up.

In MC34709 datasheet, there is a power-up sequence for processors.

However there is no descriptions about the power-down sequence.

- What is the power-down sequence of MC34079?

- What will happen in i.MX502 if it's not power-down in the reverse of the power-up as instructed in the datasheet?

BTW i.MX503 can be powered down "Switch all supplies down simultaneously".

Best regards,

Nori Shinozaki

Re: i.MX502 & MC34709 Power-down sequence

igorpadykov — Mon, 23 Feb 2015 09:31:42 GMT

Hi Nori

you are right that MC34079 datasheet has not descriptions

about the power-down sequence, that means that its supplies are

turned off simultaneously.

It was confirmed by app team that for i.MX50

basically, all power rails can be down at the same time.

Best regards

igor

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Re: i.MX502 & MC34709 Power-down sequence

norishinozaki — Mon, 23 Feb 2015 10:07:26 GMT

Hello Igor,

Thank you!

Best regards,

Nori Shinozaki

Re: i.MX502 & MC34709 Power-down sequence

norishinozaki — Thu, 17 Mar 2016 06:44:33 GMT

Hello Igor,

You wrote "all power rails can be down at the same time."

I understood that there is no power-down sequence, NO need to shutdown all power rails at the same time.

My customer is just power-down at the same time, but actually the rails go down randomly.

In this case, they need to assert POR_B before beginning power-down.

Otherwise i.MX502 pins emit strange outputs during power-down.

Have you heard about this?

Is it OK with POR_B first then power rails go down randomly?

Best regards,

N.Shinozaki

Re: i.MX502 & MC34709 Power-down sequence

igorpadykov — Thu, 17 Mar 2016 07:44:13 GMT

Hi Nori

yes it is ok with POR_B first then power rails go down randomly.

Best regards

igor

Re: i.MX502 & MC34709 Power-down sequence

norishinozaki — Thu, 17 Mar 2016 09:26:28 GMT

Hello Igor,

Thanks!

N.Shinozaki