Hi,
I built up a MAX038. I get a sine wave with the peaks slightly skewed. Does not matter what frequency it is set to.
The supply voltages are +/- 4.92V.
What causes this slight shift? Any ideas what to look for?
I used this circuit:
www.kitsrus.com/pdf/k101.pdf
Thanks.
I built up a MAX038. I get a sine wave with the peaks slightly skewed. Does not matter what frequency it is set to.
The supply voltages are +/- 4.92V.
What causes this slight shift? Any ideas what to look for?
I used this circuit:
www.kitsrus.com/pdf/k101.pdf
Thanks.
Attachments
You need to lift pin 7 (DADJ) from GND and make it adjustable between a volt or so pos and neg - something like the FINE adjust but then between + and -. That will let you adjust the symmetry of the waveform.
One way to test it is to look at the square wave output (NOT the sync output - that is always 50%) and adjust as best as possible for 50% duty cycle.
It's all in the data sheet, by the way...
Jan Didden
One way to test it is to look at the square wave output (NOT the sync output - that is always 50%) and adjust as best as possible for 50% duty cycle.
It's all in the data sheet, by the way...
Jan Didden
Doesn't look like a symmetry problem. I'd rather say there is some leak from the square wave to the sinewave, perhaps caused by charge injection or something similar.
Might be caused by a poor layout, or it could happen internally in the MAX038. Even if this is the case you could correct it by injecting a square of opposite phase into the sine output, through a high value resistor f.e.
Might be caused by a poor layout, or it could happen internally in the MAX038. Even if this is the case you could correct it by injecting a square of opposite phase into the sine output, through a high value resistor f.e.
actually, I just cut and pasted a sine wave from the wave
to show as an example of what I see on the oscilloscope
my respects to your great attention to detail.
I had the max 038 part so I wanted to give it a try.
it's working but not great so I need to spend some more
time on it.
to show as an example of what I see on the oscilloscope
my respects to your great attention to detail.
I had the max 038 part so I wanted to give it a try.
it's working but not great so I need to spend some more
time on it.
Bengali said:actually, I just cut and pasted a sine wave from the wave
to show as an example of what I see on the oscilloscope
my respects to your great attention to detail.
I had the max 038 part so I wanted to give it a try.
it's working but not great so I need to spend some more
time on it.
So maybe there isn't a problem at all. Maybe a pic of the scope screen would be more clear.
Jan Didden
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