BQ76940: AFE getting damage

Hey Pranay,

Your C49 should be connected to ground. You're also missing component D1 on your schematic. Also I noticed that there are 0 ohm resistors between C17, C16, and C15 nets. If these are populated it could be causing issues. It also looks like C5 bypasses the required diode to VC5X completely. Same situation with VC10X.

I don't see anything else immediately wrong with your circuit. See if my suggestions help and reach out if you have any more issues. 

Thanks,
Caleb

Hi caleb, Thanks for your valuable feedback .

1) Okay we will implement your solution , connect C49 to ground. but i have seen your reference design TIDA-00792 C22 not connect to ground & D1 not use. can it cause AFE internal 3.3V LDO  Damage ?

2) 0 ohm resistance are DNP part in production. (use only in 17s to 16s cell configuration. 

3) can you review again, i don't  think we bypass the require diode 

Can we share the damage part to you for evaluation ? 

Hey Pranay, 

You can send the part back to us for failure analysis by following your specific procedures outlined here. https://www.ti.com/support-quality/additional-information/customer-returns.html 

Please be advised that if you choose to initiate a failure analysis, support will be handled by a different team and I will no longer be supporting you through this thread. Let me know if you decide to return so I can close the thread accordingly.

Thanks,
Caleb

Hi caleb, 

Extremely thanks for connecting to failure analysis team 

We are planing mass production of 16S_bms with this design. 

Just acknowledge me, did you re-verify that  was attached in last conversation. 

Please help us to validate our design. 

Could you go throughout layout design for the same https://drive.google.com/drive/folders/1maxmBPzjpXknBcLL-eGNtn6pBz0vsQOE?usp=sharing

Hey Pranay, 

I took a look at your schematic and layout and they look fine.

Did you test all 300 chips on the same board? If so I would send to FA. Otherwise it might have been bad components on the other boards.

Thanks,
Caleb

Hi caleb, 

Yes, we had test all 300 chips on the same board, out of 3 AFE internal LDO damage and REGOUT & VSS geting short. 

All these board manufacture through JLC PCB in china. and the Batch NO of AFE : 0CADNGT G4  BQ7694003 .

https://drive.google.com/file/d/1fCc68QgND9M_fZqaYysfel8fXwixlre6/view?usp=sharing

did this AFE is original ?

Hey Pranay,

The failure analysis team will be able to tell you if that your parts are genuine.

Thanks,
Caleb