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LM4952: LM4952 Ground Question

Rocketman46
Intellectual 560 points
Part Number: LM4952

Hi All,

I am currently using one channel, channel A (pins 2 and 4) on the LM4952TS chip.  

My question is what do I do with the unused channel B pins.  Do I short pin 8 (-VIN B) and pin 7 (VOUT B) to GND?

Look Forward to your reply.

Cheers,

  • 0
    TI__Guru* 95335 points
    Hi Rocketman,

    One thing you can do is to leave both pins (7 and 8) floating.
    Other thing would be to connect pin 8 to GND using a capacitor and leave pin 7 floating.
    The reason I recommend to leave pin 7 (output) open is to avoid any possible short-to-GND-like situation on this pin, and also this could help on power consumption.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators
  • 0 in reply to Ivan Salazar
    Intellectual 560 points
    Hi Ivan,

    Thank you for your reply. I have implemented the below changes:

    * pin 8 to GND using a 100nF capacitor.

    * left pin 7 floating.

    Thanks,

    Rocketman
  • 0 in reply to Rocketman46
    Intellectual 560 points

    Hi again,

    Just a couple more questions.

    1) CIN A capacitor displays a non polarised capacitor in series  Would a ceramic X7R 16V be OK in this applaication?

    2) COUT A capacitor displays a non polarised capacitor in series.  Can I use a 25V electrolytic capacitor to GND in this application, or can you recommend a capaitor?

    Many thanks,

    Rocketman46

  • 0 in reply to Rocketman46
    TI__Guru* 95335 points
    Hi Rocketman,

    The output capacitor (COUT A) is connected in series to remove the DC component of the output signal, as the output is centered on VDD/2. The DC in the output signal could damage the speaker. So the recommendation is to place the output capacitor in series.
    CIN A is fine.

    Best regards,
    -Ivan Salazar
    Applications Engineer - Low Power Audio & Actuators