5V supply for MC9S12ZVCA - How to Connect?

[marks]

Hello,

We would like to use the MC9S12ZVCA with a 5V supply. How should the 5V supply be connected? Can we just wire the 5V to the VDDX, VDDC, etc., supply pins on the 9S12 and, if we do so, do we also need to wire 5V to the VSUP, even though the LDO won't be working at that point? Also, are the any low-voltage detect circuits associated with the VSUP (as opposed to VDDX) that would keep this approach from working and are the any low-voltage detect circuits that need to be accounted for in software?

Thank you!

Mark

[RadekS]

Hi Mark,

In this case I would recommend shorting all 5V supplies (VDDA, X, C) together to VSUP and supply there 5V. While there is no direct supervision on VSUP we would reversely operate the vreg which is not good because it creates substrate current for all circuits hanging off VSUP.

VDDC reg should stay enabled and VDDX configured as internal in software in this case.

Of course we probably cannot effectively use BATS module, but we still have at least LVI at VDDA and LVR at VDD, VDDF and VDDX domains.

I hope it helps you.

Have a great day,
RadekS

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------