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PCM1754-Q1: output low pass filter

Dongbao Zhou
Expert 4000 points
Part Number: PCM1754-Q1
Other Parts Discussed in Thread: OPA1642-Q1

Hello,

Could you help review the schematic of PCM1754-Q1? 

  • I recommend customer to add 1uf and 0.1uf capacitor as close as possible to Vcc pin, while in ds only 10uf capacitor is suggested, need check with you.
  • Could you let me how to design the external low pass filter?  What are the recommended parameters of capacitors and resistors (fig25,fig31)?
  • Could you also recommend an automotive grade amplifier for low pass filter? Can we use 1st order low pass filter without an amplifier?

Thanks.

Dongbao

  • 0
    TI__Guru 53453 points

    Hi Dongbao,

    I think the addition of a .1uF cap very close to VCC is a good idea.  Below is a couple examples of the LP filters you could implement. 

    You could consider the OPA1642-Q1, though I would suggest you ask the opamp forum to see if there is an other recommendation.  

    The difference between a passive RC and Active 2nd order is the amount of attenuation of the output of band noise.  There is a good article comparing the two:

    Thanks!

    Paul