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LME49710NABD: LME49710

Prodigy 95 points

Replies: 16

Views: 1086

Part Number: LME49710NABD

Good morning to you all.

What I ask is to know if possible the reason why LME49710 inserted as a buffer in the filter of which I enclose the wiring diagram, produces noise in the low pass section of the filter.

In my opinion it is the classic 50/100 Hz noise but I can not be sure because I do not have an analyzer.

The strange fact is that by putting back into the OP27 circuit of AD the noise disappears completely, even with an OPA134PA the noise is non-existent.

In the wiring diagram there are no 10 mF electrolytic capacitors that you suggest to use in the LME49720 datasheet that I have inserted.

Looking for a solution to the problem I noticed that many integrated require measures for their use as a buffer, this also applies to LME49710?

I inserted a double diode bridge in the power supply which I enclose the wiring diagram, and I also replaced the BD139 with a 2SC2660 the noise with OP27 is always inaudible but returns when I replace it with LME49710.

I want to clarify that the other integratiti have always been and are currently the LME49720, also also with the "noise" the sound quality that gives LME49710 is fantastic, the detail is something "super".

I have owned LM325 for years but I think it is time to change, so what can I use to get better nutrition than the current one. As usual, I would like to use only your components that I think are unparalleled.

The LME49710s were bought by me by Mouser.

Thanks for your help.

Sincerely, I greet you

Guido Bullo

  • In reply to kai klaas69:

    ciao kay.

    lo dico nella mia lingua al fine di esprimere quello che sento|

    grazie di cuore per aver risolto i miei problemi

    Guido Bullo

  • In reply to guido bullo48:

    Ciao Guido,

    il tuo inglese è perfetto!

    Cari saluti da sud della Foresta Nera (Germania)...

    Kai
  • In reply to kai klaas69:

    saluti dalla regina del mare, sono Veneziano.
    ciao
  • In reply to guido bullo48:

    Hi Kai

    Happy New Year to all.

    I ask you the last thing about the filter!

    I can reduce the resistance R27, R28, R29, R30, R39, R40, R41 to 1K.

    Thank you all

    Guido Bullo

  • In reply to guido bullo48:

    Hi Guido,

    a Happy New Year to you, too!

    The most noise is generated in the active filters and not in these resistors. So, I see no benefit in reducing R27...R30 and R40...R41.

    When using the OPA2132 and OPA2134 the minimum output load per OPAmp is 600R. So, reducing R27...R30 and R40...R41 to 1k would be possible. But with the TL072 the minimum output load per OPAmp is 2k and reducing these resistors cannot be recommended then.

    Kai
  • In reply to kai klaas69:

    grazie
    Guido Bullo

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