TDA8950J help understanding pinout

[vhperaltaj]

Hi, I would like some help understanding the behavior I'm observing with some TDA8950J ICs. I have three of them, and they came from two different sellers. Before installing them in the circuit, I decided to do some testing with a multimeter. Two of them show low resistance between pin 23 (MODE) and the thermal ground pad, and high resistance between pin 17 (VSSD) and the thermal ground pad, which shouldn't be right. Then I tested the third one, which came from a different seller, and this one tested as expected, with low resistance between pin 17 and the thermal ground pad.

I decided to install one of the "weird" ones in the circuit, and it immediately blew, which I expected. Then I installed the one that seemed fine, and the circuit worked perfectly.

Now, I understand that these amplifiers are not recommended for new designs, but this is an old design, and I just want to know if perhaps the one behaving strangely might be a different revision, and the seller got confused, although I couldn't find any information supporting this theory. Alternatively, maybe this seller is not trustworthy and the parts are defective.

Additional note: Here are the complete marking codes if it helps:

The ones behaving strangely:

• TDA8950J
• CMD082
• TSE15070

The one that was fine:

• TDA8950J
• CAR553
• TSE12281

[JozefKozon]

Hi Victor,

it is important to purchase our components only from our authorized distributors. Please share the names of the distributors you have purchased the components from. Please see this link for a list of our authorized distributors. 

Unfortunately if you have purchased our components from other source, there is a high risk that the components are not genuine.

With Best Regards,

Jozef

[vhperaltaj]

Hi, thanks for the swift response.

The part that works fine came from either Mouser or Digikey, not sure which one since it was bought long ago, normally that’s where I would get them, but since this part is marked as obsolete there is no stock left.

I just want some confirmation, there isn’t any other revision of this part that might behave like I’m observing right?, the most likely explanation is that the part is either defective or counterfeit?. I just want to know this for certain, so I can to talk to the seller before outing them, as far as I know this could be a misunderstanding and I just don’t want to accuse them in a public forum if I’m not certain of what happened, since I’ve bought from them in the past and always have been legit. 

[JozefKozon]

Hi Victor,

since you have confirmed that your design is correct with the correct TDA8950J, yes the other TDA8950J is either defective or counterfeit. If defective, then it should be returned to the seller under guarantee. If counterfeit, then unfortunately we cannot support you. 

Best would be if you can create a new case here for our commercial team to check if the components are genuine. 

They will definitely need pictures of the top of the failing components and possibly pictures of the packages in which the components came, to check if they can trace the delivery path. If you have purchased the components from our authorized distributors, then the components are definitely genuine. If from other source, then unfortunately they can be fake.

With Best Regards,

Jozef