Regarding i.MX6 external pull up supply for SNVS_IN

[Paul_Kang]

Hello,

Because of power leakage issue, customer wants to use pull up resistor with connected to other 3.3V or 3.15V instead of 3.0V which is connected to VDDSNVS_IN for the pins such as POR_B or BOOTMODEx

pin. Customer may use 68K or 100K resistor so even there is voltage difference, it is small voltage difference and connected thru large size pull up reisstor so it may not damage the pins.

Could you let me have your opinion if my understanding is correct and it is applicable to customer design?

Best regards,

Paul

[ZeeFrench]

Hi Paul,

Take care VSNVS voltage got a maximum rating of 3.3V, even 3.15V nominal would require below 10% precision.

If they want to connect those pullup to a different voltage than VSNVS, this is a violation of power supply group, depending on voltage sequence (like in modes where only VNSVS is present), you can power part of the chip through that I/O and not something to advice in any case.

This might not be the same as what you describe as leakage but the problem we had on this rail with first generation of PFuze PMIC was the limitation of current to 200 and 400 uA (this is being increased on latest revision) meaning you really had to count every resistor on that rails : POR_B got internal pull up, no need to add external, on BOOT_MODEx pins could be as high as 100 K (got confirmation from analog team) unless you want to boot from fuses. Check also TAMPER, TEST_MODE, ONOFF, and PMIC_STBY, PMIC_ON also on that rail.

Cheers, Philippe.