Hi! I'm using AD8510 to invert input signal from DAC (G = -1). I have made this circuit on particular small PCB to test it:
All of elements are SMD's and all of the wires are as short as possible.
My problem: When I start this circuit and connect input to the ground I have a sin wave on output with ~2.4V amplitude (f = 1.09 MHz)! If I set input voltage to 1V or 2V, for example, - output sinusoidal signal moves down properly. But I can't get rid of the output sinus. Sometimes it disappears by itself and I can't identify the reason of this. I have checked the mount, resolder all of elements - nothing. So, it seem like self-excitation of AD8510. How can I solve this porblem? What am I doing wrong?
Thank you, you are right! I tried 4.7k, 4.7k and 2.55k (all that I had) and the output sinus has disappeared. Now the circuit is stable. Adding a 10pF capacitor across the feedback resistor has reduced the settling time of output voltage and the transient of output voltage became aperiodical. So now It works perfect.