Regarding SBC IC UJA1168A failure

[Vikas_Ghadage]

We've encountered an issue during hardware testing where our product's SBC IC, the UJA1168A, experiences a short circuit on its 5V output, resulting in a continuous draw of 210 to 220mA when the input supply exceeds 5.5V. Despite our testing engineers' assurance that no scenario involves a 5V short to ground, we're puzzled by this behavior. Could you provide insights into the potential failure causes and circumstances under which the IC behaves as described?

[Vikas_Ghadage]

We've encountered a voltage drop issue at the V1 pin, with the power supply consistently drawing 210mA to 220mA. It appears that the SBC IC's 5V source is short internally. Despite testing confirming no short circuit between the V1 pin and GND, we're seeking insight into the potential causes of this source failure.

[JozefKozon]

Dear Vikas,

please share your schematic with voltage levels and part values. Is any other pin shorted to GND? 

With Best Regards,

Jozef

[Vikas_Ghadage]

Kindly consult the attached schematic for your guidance. Our test case involves verifying the analog input at the microcontroller level, linked to the V_+5V. During the analog input test, we encountered the SBC consistently drawing a current of 210-220mA. Upon thorough debugging, we identified that the SBC IC is exhibiting significant heating issues.

[JozefKozon]

Dear Vikas,

thank you for the schematic. Could you please disconnect the V1 pin from the uController and power the UJA1168ATK? To confirm that there is no short circuit on the uController side.

With Best Regards,

Jozef

[Vikas_Ghadage]

Dear Jozef,

Thank you for your prompt reply.

Currently, two samples are exhibiting the same failure. I disconnected the Microcontroller supply from both samples and tested them with a power-up. I observed the same issue. Additionally, I tested the resistance between Pin V1 and GND, and it measured 1 ohm and 1.2 ohms, respectively.

Now, it is certain that the internal power supply is short. Need to look into the possible causes of failure.

[JozefKozon]

Dear Vikas,

thank you for conducting the tests. The two UJA1168A pieces are clearly faulty. Please start a CQI (Customer Quality Incident). Procedure is, that you contact a distributor from your area, preferably the one, from who you have purchased the components, he/she will let you fill a CQC (Customer Quality Complaint) report, will take the faulty components and send them to NXP for analysis to find the root cause of this issue. Please see this link for a list of our authorized distributors.

With Best Regards,

Jozef

[JozefKozon]

Dear Vikas,

could you please share your test diagram? Which pin have you tested to connect to GND? If the V1, then the 210mA to 220mA value looks ok. Please refer to the Table 59. in the UJA1168A datasheet. The V1 output current during short circuit is defined from -300mA to -150mA. 

With Best Regards,

Jozef