ants
Full Member level 4
I had a board made up recently using the OPA548 opamp. I can't get the opamp to work properly, I've stripped everything else off the board and the amp is causing the problem. I've checked the soldering, I've checked that the pins are getting power from the rails. I just can't work out what is going on.
As i've now stripped everything the input is a signal from a signal generator. I find that no matter what voltage I input the opamp pin only takes a tiny amount of that voltage. I have also found that the input pin seems somehow to be connected to the V- pin (it is a dual supply). The chip has a current limit which I set to give up to 5A, the feedack resistors set the gain to 2. I didn't put the caps exactly on the pins a mistake that shouldn't cause this much of a problem.
Essentially I input 5V sine and get a sine wave of about 300mV superimposed on -11V. What is going on? Any suggestions?
Thanks,
Ant.
As i've now stripped everything the input is a signal from a signal generator. I find that no matter what voltage I input the opamp pin only takes a tiny amount of that voltage. I have also found that the input pin seems somehow to be connected to the V- pin (it is a dual supply). The chip has a current limit which I set to give up to 5A, the feedack resistors set the gain to 2. I didn't put the caps exactly on the pins a mistake that shouldn't cause this much of a problem.
Essentially I input 5V sine and get a sine wave of about 300mV superimposed on -11V. What is going on? Any suggestions?
Thanks,
Ant.