MPC5746 Internal TVS current level

[RheaGao]

Hi,

 I am using SPC5746R chip to design the minimum system with 1.25V using the following same circuit. During the debugging process, I found that 5746 would not work if I did not add Clv 1uF buffer capacitor to write the program with 200M main frequency. Specifically, I was stuck in the clock initialization and could not pass.  What mechanism triggers the microcontroller to cause this?  Thanks!

[lukaszadrapa · Accepted solution]

Hi Rhea,

Do you mean that 1uF capacitor is the only one at VDD_LV? The specification says that minumum capacitance is 4.7uF:

And it’s minimal value. It should be validated by user for given application.

It is also recommended to use Progressive Clock Switching feature to avoid current spikes. Search for „Progressive Clock Switching“ in the reference manual for details.

Regards,

Lukas