DRV8343-Q1: Chip burnt

Hi Matt，

Customer has tested that the power supply voltage has risen to more than 30V, but not more than 65V.

Thanks,

Annie

Hi Annie,

How does the customer set the speed to zero? Are they asserting ENABLE or shutting off any reverse polarity protection devices?

Can I take a look at the schematic?

Thanks,

Matt

HI Matt,

Turn off PWM directly. Following is schematic:

Thanks,

Annie

Hi Annie,

I would not recommend having capacitors in parallel with the gate drive current limiting resistors. This could have unintended effects.

I do see that the customer has a reverse blocking diode from +24V_P to +24V.

Can you check the voltage at VCP, VM, and VDRAIN on an oscilloscope when they are decelerating?

Can you send an image of the damaged IC so I can check where the damage location is?

Thanks,

Matt

Hi Matt,

Some ICs have obvious burn marks, just about 2mm in the fourth pin VM plastic package. Some have no burn marks, but the IC is also broken. What happens if the capacitor is connected in parallel with the driving resistor?

Thanks,

Annie

Ho Annie,

Do you have a picture? I can overlay the image with the die and see where the damage is occurring more accurately.

When the capacitor is connected in parallel with the driving resistor, it can cause some charge to get coupled from the MOSFET gate onto the GHx or GLx pin. This charge injection could pump up the charge pump and possibly cause damage.

Thanks,

Matt

Hi Matt,

This is the burnt chip.

Thanks,

Annie

Hi Annie,

That damage location is right on top of the charge pump & VM/VDRAIN ESDs.

Possible failure modes are:

• VM/VDRAIN overvoltage causing ESD damage
• VCP overvoltage causing VCP-VM damage (can you check the VCP voltage during operation to see if it is higher than expected?)

Thanks,

Matt

Hi Matt,

Customer bought the chip and tested it. He has captured the VM waveform before, as shown in the picture

Thanks,

Annie

Hi Annie,

If I am reading that right, VM looks like it goes much higher than >60V. Or is the scaling on the probe wrong?

Thanks,

Matt

Hi Matt,

Customer said it was no error. His position in the straight line is 24V, and this can’t reach 60, about 37V.

Thanks,

Annie

Hi Annie,

OK, I think we can say that the scenario of VM exceeding abs max rating is unlikely.

What about VCP - can you check to see if VCP voltage is higher than expected?

Thanks,

Matt

Hi Annie,

Any further feedback here?

Thanks,

Matt

Hi Matt,

The customer did not give me any response. You are able to close this thread now. Once there is feedback, I will let you know.

Thanks,

Annie

Thanks Annie!