Thanks, changing C5 makes no difference......i had C5=3n3 and it made it no better.
I removed R23 and shoved 3.2A through the ACS722 current sensor from a lab PSU….with the vicor dcdc module not running, and there is then no oscillation problem…..so it looks like this is the vicor DCDC module causing noise which makes the ACS722 current sensor oscillate in its signal output from its VIOUT pin
The oscillation at the signal output of the ACS722 Hall sensor gets twice the magnitude when I connect the Hall sensor for 80khz bandwidth, instead of 20khz.
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Ive a terrible feeling that since the ACS722 is a Hall sensor, it relies on having a precise magnetic field inside it…and very possibly, with the sensor being just 1cm away from a powerful DCDC module (as shown attached) , the magnetic field inside the ACS722 Hall sensor chip is getting disturbed….producing the oscillation. Would you agree?
We wanted to use the Hall sensor because it is isolated…..and the control ground , where the current measurement will be used, is not the same ground as the output ground of the DCDC module….so an isolated Hall sensor seemed like the best choice…no I don’t believe it is.