Issue with CAN Transceiver Overheating on KW45B41Z-EVK Board

[priyanshua1]

Hello,

I’m currently working with the KW45B41Z-EVK BLE board to implement CAN transmission and reception. Initially, I used NXP’s SDK example “FlexCAN Interrupt Transfer”, but I couldn’t detect any transmitted frames on the CAN bus. Upon further investigation, we found that the onboard CAN transceiver (TJA1057GT/3J) was overheating. While the exact root cause is still under analysis, we suspect it may be due to the voltage regulator (NCP1117ST50T3G) not supplying the correct voltage to the transceiver or its associated components.

I measured the voltage at pin 3 of the TJA1057GT, which is expected to be 5V, but I observed 10V instead. Additionally, I checked pin 2 of the voltage regulator IC (NCP1117ST50T3G), and it also shows 10V.

Could you please assist me in identifying and resolving this issue? Additionally, I would appreciate your help in determining the root cause. I’ve ensured that the power supply is consistently correct, so I’d like to understand whether the board itself might be defective.

[luis_maravilla]

Hello,

Could you help us share a description of your setup connections including jumper configuration? Also, a photo would be highly appreciated.

In the [example_board_readme file] the board connections from 2 sets of boards are shown. 

luis_maravilla_0-1762556952408.png

Could you help us describe and bring details about your supply source in J9, please?  As this supply P5V_CAN and this should be 12V.

Could you help us clarify where you're placing the other probe to complete the voltage measurement? You mentioned Pin 3 of the TJA1057GT/3 for the positive lead — with respect to which point is your measuring?

Best Regards

Luis

[priyanshua1]

Hello,

In response to your queries:

1. I have not made any changes to the jumper configuration. For your reference, I’ve attached an image showing the current setup.
2. I’ve modified the FlexCAN_Interrupt_Transfer project so that the board operates as a single node, transmitting CAN frames over the CAN bus. I tested this same project on another identical BLE board, and it worked correctly there—indicating that the issue lies with the board itself, not the project.
3. The board is powered using a 12V supply connected to J9.
4. The voltage at pin 3 of the TJA1057GT was measured with respect to TP17 and also TP18 on the board. I’ve attached a reference image for this measurement as well.

Please let me know if you need any additional details. KW45 Voltage Mesasurement.jpgKW45 Configuration.jpg

[luis_maravilla]

Hello,

In the KW45B41Z-EVKUM User Manual figure 7 CAN/LIN power we can see part of the schematic, the measurement you comment is with the supply of J9; to supply from P12V_VBAT you can connect  CAN header J10 PIN 3 power supply pin as the table 8 "Power supplies" said that produces P5V_CAN supply that supplies power to CAN Transceiver U7 [TJA1057GT/3].

Could you help us confirm if you change the supply source from J9 to CAN header J10 PIN 3 power supply pin, the issue still remaining?

Also, as another test, could you help us measure pin 3 [VIN] NCP1117ST50T3G [U6] and share with us the input voltage?

Best Regards

Luis

[priyanshua1]

Hello,

Please accept my apologies for the delayed response.

I have verified the input voltage at pin 3 [VIN] of the NCP1117ST50T3G [U6], which measures 11.45V and the output voltage comes out to be 10.11V at pin no. 2.

Furthermore, I have conducted a test on another KW45B41Z-EVK board using an identical setup, including the same CAN module and a 12V power supply adapter, and confirmed its perfect functionality.

Currently, I do not have access to an external DC power supply to test via the J10 power pin.

Therefore, I kindly request your assistance in identifying the root cause of the CAN transceiver's non-operational status. The primary objective of this correspondence is to conduct a Root Cause Analysis (RCA) for the overheating and malfunction of the CAN on the KW45B41Z-EVK.

Your prompt response would be greatly appreciated.

Sincerely,

Priyanshu

[luis_maravilla]

Hello Priyanshu,

The CAN transceiver [TJA1057GT/3] receives its power supply from the voltage regulator NCP1117ST50T3G [U6], as specified in KW45B41Z-EVKUM table 8, P5V_CAN supply is 10v instead of expected 5v.

Therefore, the failure observed in CAN transceiver might come from P5V_CAN supply, additionallyLVCH1T45 [U5 and U8] used in CAN are also powered by this same source. [Information from KW45B41Z-EVKUM figure 15]

Could you help us review Capacitor C60, C61, C62 to try to check if they are working as expected or perhaps interfering with internal configuration of NCP1117ST50T3G [U6], also confirm that pin 1 (GND) of NCP1117ST50T3G [U6] is properly grounded; And could you confirm the marking label on the top of the device NCP1117ST50T3G [U6]?

Best Regards

Luis

[priyanshua1]

Hello,

U5 and U8 have the same voltage as can transceiver.
Pin 1 (GND) of NCP1117ST50T3G [U6] is properly grounded.

I was unable to check capacitors.

thank you