Are external regulators necessary when using i.MX RT1172 Automotive at 800MHz?

[Ryo_Aoki]

Hi NXP.

The i.MX RT1170 Automotive datasheet states that when (600 MHz < fCM7 ≤ 800 MHz, fCM4 ≤ 400 MHz), the internal DCDC converter is bypassed and an external regulator is required.

I believe that an external regulator is required even for i.MX RT1172 (only CM7) at 800MHz, is this understanding correct?
Does the presence or absence of CM4 affect whether an external regulator is required?

Best regards.

[_Leo_]

Hi,

Thank you so much for your interest in our products and for using our community.

The recommendation to use the PMIC or external regulator depends not only on the frequency, but also on the temperature.

You could also find useful the app note AN13213 Using i.MX RT117x Processor with PF5020 PMIC for Auto Application.

Hope it helps you.

Have a nice day!

[Ryo_Aoki]

Hi Leo.

Thank you for your reply.
 -If Tj is below 105 degrees and 800MHz, it can use internal DCDC converter.
 -If Tj is below 125 degrees and 800MHz, it need to use PF5020.
 -And this condition is not affected by the presence or absence of CM4.

This is my understanding, but is this correct?

Best regards.

[_Leo_ · Accepted solution]

Your understanding is correct!

[Ryo_Aoki]

It was very helpful.
thank you!