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LM49450: Selection Help

Scutarius
Prodigy 60 points
Part Number: LM49450
Other Parts Discussed in Thread: LM4935, TAS5102, TAS5705

Hi,

I am working on a project (Bluetooth stereo speaker) that requires:

  1. 2x 2W or 3W speaker
  2. headphones output
  3. Stereo Input (AGC?)
  4. subwoofer output , 20W, with a knob to select cut-off frequency. 

For 1 to 3, LM49450 seems to do the job

I have two questions, 

1) How can I add AGC (automatic gain control) to my stereo input? similar to the LM4935, now obsolete

2) what is the simplest way to add requirement 4? I am assuming an analog input is going to be easier to change the cut-off fr (knob)

I like the application diagram of TAS5705 (datasheet page 2) that uses TAS5102 for the subwoofer, but TAS5705  lacks the Aux input

Thank you, 

  • 0
    TI__Guru** 102045 points

    Hi Scutarius,

    If you go for analog input option on requirement 4, you may look into the TPA31xx family of amplifiers. You could use the same analog input signal that goes to LM49450 and add a low-pass filer at the input of the TPA31xx.

    If TAS5705 & TAS5102 seems OK, you could just add an ADC, like TLV320ADC31xx or PCM186x, that takes analog input into digital, then use some switch or mux to change between the modes.

    Best regards,
    -Ivan Salazar
    Applications Engineer