> I find that the output of my DDS-60 card is actually around 800 mVPP
> into a 50 ohm load; down from the published 2-3 VPP.
> Further investigation reveals that the output of the AD9851 chip at
> the input to the eliptic filter is actually around 50 mVpp rather than
> the expected 200 mVPP.
> Has anyone else run into this problem?
> Anyone have any suggestions? I've already temporarily changed the
> value of R10 on the RSET pin to 3.9K, which brought up the output to
> Bob WA6UFQ
Isn't the max output only about 1 VPP according to the specs.
Rset=3.92k gives a max output current of 10mA, 500 mV into 50 ohms.
This assumes that the nominal max current is 10 mA. However, the spec
is pretty broad, and can be as low as one half of that.
Can't you decrease the value of Rset below 3.9K and get even more
output? What value were you using previously?