AD9833: Sine generator

Document created by analog-archivist Employee on Feb 23, 2016
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What is the precison can I except on temperature range: the output is 0.65V max
+/- ???
Do you confirm that the rejection of 2nd harmonic is 65 dB.

 

The frequency precision of any DDS system is as good
as its reference frequency. The AD9833 & AD9834 use
external reference source, so that reference must have
the frequency stability that you need in your system.

The output of the DAC is a current into a 200 Ohm load.
The scale factor is defined by the reference. The AD9833
has a TC of 200 ppm/°C (Max) and the AD9834 has a TC of
100 ppm/°C (Max) so the worst case amplitude stability
will be 200 or 200 ppm/°C depending on which device you
choose.

The THD of these devices (sine wave output) is typically
-66 dB, but can be as bad, at some frequency codes, as
-56 dB. You should be able to build a generator with
-65 dB 2nd harmonic without much trouble if you can choose
your reference frequency/division ration or use quite a
simple filter at the output (or, of course, both).

To raise the current output of the device to a 10V p-p
signal you should use an op-amp in I-V mode.

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