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Original question:

LM48100Q-Q1: Noise in speaker output.

LM48100Q-Q1: Continuous noise on speaker output.

Rahul Patil
Prodigy 20 points
Part Number: LM48100Q-Q1

Tool/software:

Hi, 

So i was working on the PCM-PWM converter on the controller which feeds the data to the LM48100Q-Q1 Amplifier. Now i am just initializing the PCM module and powering on the Amplifier with maximum Volume setting. I am able to hear continuous noise(hissing sounds) on the speaker even though i am not sending any data to the input lines of the amplifier from the controller ??? What might be the issue here ?? 

Thank You.

  • 0
    TI__Mastermind 42130 points

    Hi Rahul

      Sounds like you are providing PWM signal to LM48100? This device is designed as analog input, not PWM input. Can't guarantee for this using.

  • 0 in reply to Shadow He
    Prodigy 20 points

    Hi Shadow,

    Yes, i agree that my output from controller end is PWM but i am not directly feeding the PWM signals to the Amplifier. I have a Low Pass Filter and a capacitance which converts the PWM signal to Analog signal. 

    Thank You.

  • 0 in reply to Rahul Patil
    TI__Mastermind 42130 points

    Hi Rahul

     The noise may not able to fully filtered at the input side, and will be amplified by LM48100. 

     Let's use oscilloscope to capture both input and output waveform at the same time, should able to find similar noise at both end.