BQ3050: BQ8050 output PWM3.3V abnormal in the high temperature

This indicates that this specific unit has a defect. Please submit a customer return request: www.ti.com/.../customer-returns.html

Hi TI engineer:

Let me add some details about the situation，for the current batch of chips, have the PWM problem described above, with a ratio of 8/210 = 3.8%.We urgently need your professional advice:

1.Risk Assessment for Shipment.

Our project has already been mass-produced into finished battery packs. After isolating the defective units, we are hesitant about shipping the remaining inventory.
Question: What is your professional opinion on the risk level of this issue? Should we proceed with the shipment, or is a more rigorous screening required?

2.Enhanced Testing Methods.

Current Approach: We randomly selected 20 battery packs for high-temperature chamber testing (4 hours), checking PWM functionality afterward.
Request: Are there any alternative or supplementary methods you recommend to quickly and comprehensively validate the PWM function of BQ chips? 

Best regards,
zehu

I cannot comment on the risk without knowing what causes this defect. And the cause can only be determined by TI if TI gets ahold of the broken gauges.

About testing: The gauge must be able to generate the PWM output within the specified recommended operating conditions (which includes temperature). If the defect causes PWM to only fail at a specific temperature range then you'd have to test this for this temperature range. I don't think that there's a shortcut that can identify devices with this defect.

Hi Zehu:

My customer have the same issue. the chip datecode is 2440. Could you share your chip datecode ? and what company do you from ? I only check if they are the same case. 

thanks.

If you have this problem, please return the failing parts to TI.

Had shipped failing parts to TI FA team. just want to discuss the root cause. 

Hi Dominik:

When the PWM is abnormal, SMBus communication with the BQ cannot be established. If a certain module of the BQ is damaged (e.g., the PWM), will other modules also be abnormal?

It's impossible to say as this is a complex integrated circuit but chances are that whatever is the root cause for the failure impacts many different parts of the system so I'm not surprised that this affects smbus comms as well.

Hi Dominik:

Is it possible that this batch exhibits PWM abnormalities around 40°C, while other batches might experience similar issues at 60°C, 70°C, or other temperature points?

thanks.

It's difficult to say. A correctly working gauge will not fail if its within recommended operating conditions.