Clarifications required in SBCFS26 VPRE Regulator Voltage Range

[Sivahari]

Hi NXP,

I need clarifications in SBCFS26 VPRE Regulator. I had analysis on MFS2613AMDA6 Datasheet for VPRE Voltage regulator. It is mentioned as FS26 is unable to provide power rails when the supply voltage range is below the VPRE_IN minimum Limit. 

As per the datasheet, it's minimum voltage range is 4.75V. If this is the case, then whether VMONPRE will trigger VPRE Undervoltage fault since its threshold value is 90% of VPRE monitoring voltage 6V?

And also, please clarify in which use case i could expect VPRE Undervoltage fault?

Thanks for understanding.

[RafaR]

Hello Sivahari

Good Day!

1.-

Yes, but only when VPRE is expected to be ON and regulated. If the device is in a mode where VPRE is enabled and regulating ( Normal mode or Standby mode with VPRE active), and the effective VPRE output falls below the VMONPRE UV threshold, the FS26’s safety monitor can flag a VPRE undervoltage fault after the internal deglitch time

2.- Some cases in which VPRE Undervoltage fault can occur are:

• Battery sag / cranking
• VSUP falling below the VPRE input minimum
• Excessive load step or short on the VPRE rail
• Misconfiguration of front‑end vs. direct‑battery topology (OTP dependent)
• Thermal or internal protection interactions

I hope this information has helped you, please let me know if you need help with anything else.

Have a great day and best of luck.

[Sivahari]

Thank you RafaR for providing the clarifications.