Hello, I am putting together an h bridge PCB where I will be using a current sensor the ACS72981 but I am confused as to what the protocol for using these sensors is in terms of connecting them on the PCB. I am using a 4-layer board where I have signal on the 1st layer, ground on the second, power on the 3rd, and signal on the 4th. the sensor is SMD so I have to drop it down to the 3rd layer through a via but can I do that? any advice would be appreciated.

 

What is the purpose of the current sensor? If you are measuring the current ramp in the MOSFETs it might be a little slow, phase shift. It is good to 250khz but that is slow if you are monitoring the current ramp.

I would connect the power supply capacitor very close to pins 1& 2, then drop down to power and ground.

 

What is the purpose of the current sensor? If you are measuring the current ramp in the MOSFETs it might be a little slow, phase shift. It is good to 250khz but that is slow if you are monitoring the current ramp.

I would connect the power supply capacitor very close to pins 1& 2, then drop down to power and ground.

The purpose of the current sensor is for me to be able to monitor the current on the board and eventually construct a current feedback loop

 

Why not connect the sense resistor in series with the bottom of the bridge to ground?
That will give you a ground based signal.

 

Why not connect the sense resistor in series with the bottom of the bridge to ground?
That will give you a ground based signal.

Can I still accomplish that with the Hall effect sensor I am using?

 

Can I still accomplish that with the Hall effect sensor I am using?

Yes.
I didn't see you were using a Hall effect sensor.
That can be put in either the high side or low side of the bridge with equal accuracy.