How small of a current can the ACS710 resolve?
The current resolution of the ACS710 family of sensor ICs is limited by the noise floor of the device output signal. For example, the ACS710-12C version can resolve a change in current level of about 163 mA, at 25°C, at full bandwidth. The ACS710-25C version can resolve approximately 213 mA. At these levels, the amount of magnetic field coupled into the linear Hall-effect IC is just above its noise floor. Resolution can be improved significantly by filtering the output of the ACS710 for applications requiring lower bandwidth. The noise level and device output current resolutions at various bandwidths, achievable through filtering, are given in table 1 for the ACS710-12C, and in table 2 for the ACS710-25C. Filtering was accomplished with a simple, first order RC filter consisting of the internal resistor RF(INT) (typical value 1.7 kΩ) and an external filter capacitor CF.
