I purchased a number of tda7297 chips from STM and they do not work. Connected to my Fluke set to ohms I get No readings at all. Yet I have Chinese supplied tda7297 chips which do give a reading.

[SHorv.1]

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[Peter BENSCH]

Welcome, @SHorv.1​, to the community!

A multimeter in the resistance measuring range is rarely a suitable instrument to test the function of a component, instead you should test the components in a real circuit.

Is it a reliable source where you bought these devices?

There are a lot of counterfeit chips nowadays. What gives you the conviction that they are original?

Regards

/Peter

[SHorv.1]

Hi Peter, Thank's for the response, I purchased the TDA7297 chips directly from ST and were supplied from Mouser. I tried on 3 occasions in a circuit and each time nothing so out of frustration checked the cheap Chinese TDA7297 chips with the Multimeter and was getting a reading, then tried with the ST supplied chips and no readings at all.

Regards Steve Horvath.

[Peter BENSCH]

OK, so it looks like these devices are genuine.

What does that mean exactly: "they do not work"?

What does your application circuit look like, what are the environmental conditions of the TDA7297 (supply voltage, load resistance, input signal etc.)?

Regards

/Peter