TDA7391PD (audio pa) pin 16,17,18 , 19 burned, any cause this issue except over voltage

[Wteoh]

I have 20 radio , 19 radio is fine but one of the radio TDA7391PD (audio pa) pin 16,17,18 , 19 burned

[MikeDB]

It's probably just 16 and/or 19 actually. Is it in bridge mode or are you using it as two separate amplifiers ?

Either way I would guess that the top output transistor has died. See if the others always survive some long term testing

[Wteoh]

We are using it in BTL mode.

If it is one of the transistor has died, can you help to advice what are most possible causes for this incident.

We are actually trying to duplicate the failure symptom here.

Vcc is 13.2V, speaker load is 16ohm.

[MikeDB]

First I would take an ohmeter to the package and confirm which transistor has died. I expect it is the upper one from positive supply to output, but best to check first. It will be <10 Ohms whereas the good channel will be high resistance. Measure in both directions though as there will be protection diodes distorting the reading.

To be honest, most IC amplifiers are pretty bulletproof and just shutdown if you short an output to ground for example. You may just have had a bad one-off device.

[Wteoh]

Thanks Alot...