S32K328 – Missing Information: Switching Frequency at PMOS_CTRL (SMPS V15 Regulator)

[MarkusÖsterle]

Hello,

I am using the S32K328 with the SMPS option for the V15 regulator.  However, I cannot find any information in the publicly available documentation regarding the switching frequency used at the PMOS_CTRL pin.

Could you provide the switching frequency used by the S32K328 when driving the external PMOS in SMPS mode? This information is required for correct inductor/diode selection.

Thank you.

[PavelL]

Hello @MarkusÖsterle ,

The information about switching frequency is not available.

The S32K3xx - Hardware Design Guidelines, Rev. E2, recommends Schottky diode and 4.7uH - 5.6uH .

The S32K3xx Data Sheet, Rev. 13, specifies 2A Schottky diode and typ. 4.7uH.

Board S32K3x8-Q289 uses PMEG4050EP and 5.6uH, as well as S32K388EVB-Q289. Detailed part number and manufacturer can be found in the BOM file for the board.

Best regards,

Pavel

[MarkusÖsterle]

Hello @PavelL ,

Thank You, this is the same Information I could find as well.

I was still wondering if it is a Problem for the IC if the inductor is in DCM which would be the case with the recommended values and a 3V3 supply voltage.

Best Regards,
Markus

[PavelL · Accepted solution]

Hello @MarkusÖsterle ,

I’ve summarized the information here so others can follow along.

Operating in DCM with the recommended component values at a 3.3 V supply is not an issue for the device.

Best regards,

Pavel