100 and 300 ohm values for the divider are way too low for the chip to drive.
You've omitted Cf, the filter capacitor, so the output will be noisy, this might be an issue for you.
Extra decoupling on the 5V rail isn't going to be a problem (its better to have too much than too
There is a minimum output load resistance of 4k7, either to ground or to Vcc, and the output
drive current is limited to an absolute maximum of 3mA to ground, hence the comment about your
100 ohm and 300 ohm divider. [ from the specs in the datasheet ]
I suggest use a 3k3 + 10k resistive divider on the output so that its not overloaded.
The output divider and the filter capacitor Cf form a first-order low-pass filter in order to limit
the noise bandwidth. For 3k3 and 10k divider the effective resistance will be 2k5, so for instance
a 10nF filter cap will give a time-constant of 2k5 x 10n = 25us (ie a noise bandwidth of about
These hall-effect based current sensors are inherently very noisy, you would normally want to set the
filter time constant appropriate to your application to reduce noise. If you want rapid response, you
have to live with the noise. Noise power is proportional to bandwidth.
This response triggered more questions, but my knowledge is limited to what I have needed to research to accomplish a goal.
i care to only sample the current once a second if that matters. should i look at another option for current sensing? my goal is to have it on the same PCB as the ESP12, I know there is amount of seperation that will need to be addressed, but i intend to offload the board design to a professional once i get the schematic down.
i inherently dont understand noise and its calculations so 25us is greek to me also the "time-constant" term.
so, as far as i understand, i need a 10nF filter cap (along with my 1000uF cap already on the rail) for Cf and 3.3k/10k resistor divider in place of Rf?
if this is true, ill add it to my schematic and get confirmation from you guys.