S32K312 100pin_Cbulk inquiry

[DennisSong]

Dear NXP Tech Team,
I am Dennis from Future Electronics.

I inquiry about the S32K312 VDD_HV_A PIN Capacitor connection, which my customer is currently reviewing.

Referring to the Application Note,Bulk capacitors are required to supply domain voltage to each pin, as indicated.

So, when referring to the images in the User Guide, is it correct to connect 1 piece of Cbulk and 4 pieces of Cdec?

Furthermore, the Application Note specifies that the value for Cbulk should be in the range of 4.7uF to 10uF, and for Cdec, it should be connected in the range of 100nF to 220nF.

On what basis should the capacitor value be chosen?

Thank you.

[VaneB]

Hi @DennisSong 

The value of the bulk and decoupling capacitors depends on your design. As stated in the Hardware Design Guidelines for S32K3 Microcontrollers: "The effectiveness of the bulk/bypass and the decoupling capacitors depends on the optimum placement and connection type."

Please refer to the schematic of the S32K312EVB-Q172 for a better reference for your design. 

B.R.

VaneB

[DennisSong]

Hi VaneB,

Thank you for your Help.

I have additional questions.

For the stability of the supply pin, users should design based on the specified predefined value in the H/W guidelines,

Does that mean understanding and verifying the optimal efficiency values of decoupling capacitors based on their placement and connection types?

Thank you.

[VaneB]

Hi @DennisSong 

The hardware design guideline is just a recommendation for customer designs. As I mentioned before, the value of the bulk and decoupling capacitors depends on your design.