KW45 MCU heating up

[Sadeed]

We have assembled Two KW45 boards, During Board bringup we are facing few issues, Which are as follows:

As per the attached schematics:

-> The KW45 ic started heating up when board was powered On and the board was drawing 0.45 Amps at 12Volts. After some Debugging activity, I have found that when R15 is removed then its drawing only 10 mA. The heating issue happens when I mount that resistor.
When R15 is removed, I have measured 1.8V at pin 21 on KW45 ic.

-> The voltage on MCU Reset pin is 2.299V; 3.3V rail has less than 100mV ripple. I have observed some kind of oscillation on that pin.

-> We have referred to page 749 found in KW45 Reference manual.

-> we are using KW45B41Z53AFTBR

-> On 5V section, I am getting 5.4V, as we have adjusted it for other requirements and in 3.3V section, it is 3.3V.

Could you please Verify the Schematics for any kind of improvement? 

______
Thanks & Regards

Sadeed

[Sadeed]

We have found that C41 and C35 were mistakenly added. After removing these two capacitors, the issue has been resolved.

Please find the relevant schematic section attached below for your reference.

[luis_maravilla]

Hello

I would recommend checking this community post as it describes Hardware design recommendations  for the connections referring to DCDC configuration in KW45.

The best way to build a PCB first time right with KW45 (Automotive) or K32W1/MCXW71 (IoT/Industrial)...

Also, Could you help us confirm what DCDC mode are you trying to build?

Please refer to page 44 for Reset configuration and Page 8 for DCDC Modes in this File "KW45 Hardware Design Recommendations Public" located in the same Community Post.

Best Regards

Luis