looking for reference circuit of AD9834 to op amp

Am trying to build a function generator that will be used in a material test system.  The output will vary across a wide range of levels and frequencies, so have been looking at the application note CN0156 which uses the FS Adjust input of the AD9834 to control the amplitude, that could work well.  This would then need to go to an op amp to deliver some power.  I just need a clean sine, not square or other waves.

Are there any reference circuits available that have any similar DDS part with output to an op amplifier?  The wide range of frequencies from .1 to >30 MHz might make the op amp selection a little challenging, but since this is like a standard function generator, maybe there are some reference circuit examples available.  Does anyone know of any?

Thanks,

Dan

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  • Hi Miguel,

    The specifics of some of the parameters are still to be determined but the supply voltage and output range would be about 20V, max current output could be about 100ma, Not sure about the impedance.  It would need high amplitude resolution so would consider using the AD5640 or AD5660. And the top frequency could be around  1MHz, it would be good to first build a prototype for testing then the ranges can be expanded later, if needed.

    If there were a generic app note showing a DDS with an op amp, that would be helpful.

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  • Hi Miguel,

    The specifics of some of the parameters are still to be determined but the supply voltage and output range would be about 20V, max current output could be about 100ma, Not sure about the impedance.  It would need high amplitude resolution so would consider using the AD5640 or AD5660. And the top frequency could be around  1MHz, it would be good to first build a prototype for testing then the ranges can be expanded later, if needed.

    If there were a generic app note showing a DDS with an op amp, that would be helpful.

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