Part Number:MSP430F5328
Hello,
I measure voltage at output of OpAmp, ADC have external reference voltage, that voltage is stable, but AVcc spikes about 25mV influence voltage at ADC input pin for the same 25mV. When I disconnect ADC input pin from OpAmp output and measure OpAmp output by oscilloscope, than spikes disappear.
Does that uC have not any suppression for AVcc spikes for voltage at ADC input pin?
I have following schematic:
Oscillogram of ADC input pin when connected to OpAmp, AVcc voltage measured near AVcc pin:
I tried the same schematic with STM32 uC, voltage spikes near AVcc pin remain the same, but they suppressed:
