Inputs to TDA7498/TDA7498E

[DDode.2]

Hi. I am planning to use TDA7498E in one of my projects and was going through the datasheet of the same and got confused at one point. In the absolute maximum ratings, it is written that the INPA, INNA, INPB, INNB have the maximum input rating of -0.3V to +4V.

The thing which got me confused is that since the analog audio signal is more or less like a sine wave with equal peaks both in positive and negative, then how are we supposed to provide the input to the TDA7498E?

[Peter BENSCH · Accepted solution]

Please have a look at the test circuit in the datasheet or the same schematic of the STEVAL-CCA044V1.

All of the pins you mentioned are connected to the analog input jack via a capacitor of 1µF, coupling the input AC voltage to the internal circuitry. The AC input voltage can therefore be fed in with reference to ground or with DC offset. The TDA7498E contains internal voltage dividers to provide some virtual ground behind all of these pins. The maximum input voltage of 4V then corresponds to an AC effective input voltage of 1.414V (4V/2/sqrt(2)).

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/Peter