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LM4902: Schematics review and o/p voltage requirement is 1.5 Vrms@150ohm.

Manjunath B
Intellectual 360 points
Part Number: LM4902

Hi ...

We are using TLV320AIC14KIDBTR and LM4902MM/NOPB in our audio processing card.

The input to the TLV320AIC14KIDBTR  will be MIC or 1.5 Vrms differential.

The output of the TLV320AIC14KIDBTR will be given as an input to LM4902MM/NOPB through analog DPDT switch.

The output of the LM4902MM/NOPB will be interfaced to a Headphone(1.5 Vrms, 150 Ohm).

Can the output of LM4902MM/NOPB be directly connected to a Headphone(1.5 Vrms, 150 Ohm) ?

Requesting you to review the attached schematics and give your feedback.

Warm Regards,

Manjunath.B

  • 0
    TI__Guru** 100135 points

    Hi Manjunath,

    The schematic looks OK.
    Regarding LM4902 output drive, you can use Figure 34 from data sheet as reference. 1.5Vrms may be too high considering VDD = 3.3V. I would suggest to evaluate this device separately to better understand how much voltage can be driven at such higher impedance load, the device does not include any spec for that kind of loads. Unfortunately there is no evaluation module available so you would need to use a breakout board or similar.

    Best regards,
    -Ivan Salazar
    Applications Engineer