I have made an inverting amp with the njm4556 first and it works fine but after that, I made a new one with the opa551 then after just 2 second turning the power on, the opamp get extremely hot. I have checked for many times but found no mistake. When I disconnect the in + terminal to the ground, the opamp didn't get hot anymore. Anyone have a suggestion?
the OPA551 isn't the most convincing "unity gain stable" part
low gain/phase margin, poor capacitive load plots
output load isolating series L, Zobel would be good ideas
inverting amps become unity gain with the input disconnected so a ~200 kHz RC input filter can help stability by shorting the input to gnd at higher frequencies
and a "noise gain" series RC shunt from op amp + to - pins can make sure the op amp sees a safer higher than unity gain near the loop gain intercept
noise gain compensation has to be designed in the frequency domain to fit the op amp gain curve and the selected closed loop gain
low gain/phase margin, poor capacitive load plots
output load isolating series L, Zobel would be good ideas
inverting amps become unity gain with the input disconnected so a ~200 kHz RC input filter can help stability by shorting the input to gnd at higher frequencies
and a "noise gain" series RC shunt from op amp + to - pins can make sure the op amp sees a safer higher than unity gain near the loop gain intercept
noise gain compensation has to be designed in the frequency domain to fit the op amp gain curve and the selected closed loop gain
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.