TDA 7294 pin layout

[Alikabir1984]

Hi everyone,

I recently purchased these chips they look original as the seller only sells genuine parts, but when I check them with a DMM, the Tab and pin 15 should have continuity these dont, Pin 15 and 8 should have continuity these dont. Can anyone help identify if my method was correct as I was following the actual datasheet for these and they dont match.

[Peter BENSCH]

The photos look like original devices, at least. In fact, TAB is connected to pin 15, so you should be able to measure continuity between them with a DMM. Are you sure you are measuring at pin 15, i.e. the furthest right pin when looking at the label and TAB is at the top?

However, pin 8 is NOT connected internally to TAB or pin 15, which would also be counterproductive, because pin 8 does not have to be connected to the same negative supply as pin 15, as you can find in the data sheet, fig. 20.

Regards
/Peter

 

[Alikabir1984]

Dear Peter,

Thank you very much for your clarification and for taking the time to review this.

I can confirm that I am measuring Pin 15 correctly (furthest right pin when viewing the device from the front, with the label facing me and the TAB at the top). On the devices in question, I do not observe continuity between the TAB and Pin 15, instead I see a high resistance of 9.36 MΩ / diode-like behavior, which led to my concern. Yes pin 8 is not internally bonded to Tab or pin 15 I misread the datasheet.

I have ordered reference TDA7294 and TDA7293 parts from an authorized distributor for comparison, and I will re-check the measurements accordingly. For now I have opted to return these kept one for comparison.

Thank you again for your support and clarification.

Kind regards,
Ali Kabir