xr2206 outputs

Discussion in 'The Projects Forum' started by Neil Groves, Oct 4, 2013.

  1. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
    3
    I have just finished my function generator project having programmed the frequencies I need (audio) and set up a nice looking sinewave throughout the range, my question is should the output be coupled such that the waveform wanders equally around the 0v rail, or should it have a D.C offset?

    do I need to buffer the output via a transistor on it's way to the output jack?

    Neil.
     
  2. crutschow

    Expert

    Mar 14, 2008
    13,028
    3,237
    Normally sinewaves go equally around 0V unless you want them offset for a reason.

    The need for an output buffer depends upon the smallest load impedance you intend to drive.
     
  3. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
    3
    I intend to use the circuit for testing pre amps and filter responses that use transistors and/or I'Cs.

    Neil.
     
  4. crutschow

    Expert

    Mar 14, 2008
    13,028
    3,237
    The sinewave output impedance of the xr2206 is 600Ω so the output voltage will be reduced by the voltage divider action between that impedance and the load impedance. For example if the load impedance were 10kΩ then the output voltage would be reduced by a factor of 10k / (10k + 600) = .943 as compared to the open circuit voltage. So you likely won't need a buffer amp for testing your preamps and filters unless you can't tolerate the voltage drop from the 600Ω output impedance of the xr2206.
     
  5. Neil Groves

    Thread Starter Member

    Sep 14, 2011
    125
    3
    The voltage drop definitely won't be an issue for me so I'll go ahead and A.C couple the output, then send it to the output jack.

    thanks Crutschow.

    Neil.
     
Loading...