AD698 Issues

Hi, i am a student of shnu.

I just follow the schematic of cn0301 to rebuild the PCB.

But i found if i plug in the AD698 . The AD698 will make a sound or squeal.

It seems like if the AD698 is pluged in,the output will have a ramp ripple.

what is the problem?

And how can i fix it.

    •  Analog Employees 
    on Apr 6, 2016 1:39 AM over 4 years ago

    Hi Sun Wen,

    Could you please clarify what you mean when you say the AD698 is making a squealing sound?  What are you doing where this is making a sound?  Is this on the CN0301 board?  Could you send any pictures of your set up? 

    When you say there is a ramp ripple on the AD698, could you describe the situtaion in which you see the ripple?  Do you have any scope shots that you could share to point out what you mean?

    Brandon

  • Thank you for the reply.

    The first question: When i put the +15V and -15V to AD698, the ic will make a sound. I have followed the design of cn0301, so ,the voltages are coming from the adp1613. When i watch the wave from oscilloscope, the output voltage  wave is like this picture.I thought it could be some wrong with the +15 and -15 power.

    The second question : I did nothing when the AD698 make a sound. I have tested that there is nothing but the supply voltage , the AD698 still make a sound.

    The third question : It is not the cn0301 board. I just follow the schematic, and rebuild the PCB.

    The 4' question: here is the pcb board.

    •  Analog Employees 
    on Apr 7, 2016 1:34 AM over 4 years ago

    Hi Sun Wen,

    I can't recreate this sound you are talking about using the CN0301 board, so I'm not sure what to do at this time.  Do you have a CN0301 board available to you?  Can you test the CN0301 board using the same setup you have on your board?  Have you probed all the voltage rails on each of the devices to make sure they are at the correct level?

    The +/- 15 volts will have some ripple on it because it's being driven from a switching regulator.  Have you tried getting any outputs from the boards?  Are you able to get anything coming out of the board?

    Could you provide a schematic of what you are doing?