These two quad op amps have the same pinout so, I can compare them in the same circuit via an IC socket.
Both work fine, the pwm outputs are good. However, there is an anomaly with the 6484 that I want to understand.
The control voltage at the bottom comparator inputs is distorted, like, "modulated" by the triangle wave (I guess)
I have drawn in approximately what it looks like on the scope with both the tri wave and the control voltage shown. The tri wave is clean and the control voltage basically mirrors it.
The LM324 does not exhibit this. With the 324 the control voltage is, as expected, a clean flat variable DC voltage.
What could cause this?
Both work fine, the pwm outputs are good. However, there is an anomaly with the 6484 that I want to understand.
The control voltage at the bottom comparator inputs is distorted, like, "modulated" by the triangle wave (I guess)
I have drawn in approximately what it looks like on the scope with both the tri wave and the control voltage shown. The tri wave is clean and the control voltage basically mirrors it.
The LM324 does not exhibit this. With the 324 the control voltage is, as expected, a clean flat variable DC voltage.
What could cause this?