topic Re: TWR-KM35Z75M U2 VOUT in Kinetis Microcontrollers

TWR-KM35Z75M U2 VOUT

cheekun — Sun, 13 Apr 2025 14:25:47 GMT

Hello.

Regarding U2 of TWR-KM35Z75M, pin 2 is connected to the 3.3V power line in the schematic, but pin 3 is connected to the 3.3V power line in the Gerber and the actual board. This is probably the reason why a voltage of about 3.9V is supplied to the MCU, which exceeds the required operating conditions. How can I make this board supply a voltage to the MCU within the required operating conditions?

Best regards

Re: TWR-KM35Z75M U2 VOUT

Celeste_Liu — Mon, 14 Apr 2025 03:44:39 GMT

Hello @cheekun ,

Thanks for your post.

Do you mean there is a discrepancy between our reference board and the schematic diagram? Or is it your custom board that has this issue?
Is the setting of your Jumper J3 correct?
Please refer to the TWR-KM35Z75M-QSG.

The doc can be downloaded from TWR-KM35Z75M | Tower System Board | KM MCUs | NXP | NXP Semiconductors

Hope it can help you.

BRs,

Celeste

Re: TWR-KM35Z75M U2 VOUT

cheekun — Tue, 15 Apr 2025 21:49:40 GMT

Celeste

Thank you for your quick response.

Yes. I think there is the difference between the reference board schematic and artwork design. The jumper on J3 is connected. However, it is possible that the board does not output 3.3V correctly regardless of the jumper on J3.

Re: TWR-KM35Z75M U2 VOUT

Celeste_Liu — Tue, 22 Apr 2025 02:06:32 GMT

Hello @cheekun ,

Sorry for the late reply. My TWR-KM35Z75M was borrowed. I just got it back and conducted the test.

In fact, I have already measured and obtained the following values:

J3-3.316 V
J6-3.316 V

U2
Pin3 - 3.3165 V
Pin2 - 4.895 V

It doesn't seem to have the problems as you described. Could you please double-check it again? Thanks for your understanding.

Have a nice day.

Celeste