The ACS726 is the first product in Allegro’s family of current sensors to include a fully differential output signal. Shown here in the block diagram, the signal path is fully differential throughout, minimizing the impact of any common mode noise in the output accuracy, both internal to the ACS726 and when the designer is routing the output on a printed circuit board. This differential output signal helps improve immunity to any common mode noise in a circuit, which can be an issue in many motor control and inverter applications. The offset drift over temperature is also more stable with the differential output. On the right hand side of the block diagram is the integrated back end amplifier. This amplifier allows the user to gain and filter the output of the ACS726 with only the addition of a few external resistors and capacitors. This allows the circuit designer to customize the gain of the part and better match the magnitude of the output signal of the ACS726 to fully utilize the dynamic range of the input Analog-to-Digital Converter. This also allows the ACS726 to be used in similar platform solutions whose power ratings vary from system to system, such as power supplies and motor drivers, as it only takes a simple change in the external resistors to optimize the output swing of the current sensor IC. Allegro has implemented its patented digital temperature compensation algorithms in the ACS726 device. The result of this temperature drift compensation circuitry is very flat error performance over a wide operating temperature range. It is important to note that this is done in parallel with the analog signal path, so there is no reduction in the overall system bandwidth as a result of this circuitry. The digital temperature compensation circuit employs an EEPROM memory that is used to store the temperature coefficients that are required to maintain a flat response versus temperature for the output signal offset and sensitivity. These coefficients are programmed at Allegro’s final test operation, so the temperature calibration is already complete when the customer receives the ICs, making them easy to use and design into ones application. The temperature compensation works well and provides a more accurate and stable output signal performance compared to previous generations of products, again, without compromising the output signal response time. While the ACS726 has a typical bandwidth of 120 kHz, the circuit designer can also use that integrated back end amplifier to filter the output of the part. The filter can reduce the bandwidth, and noise, by adding external capacitors to the feedback network around the back end amplifier. The ACS726 is provided in a very small footprint automotive qualified QSOP24 package. This package has an integrated primary conductor resistance that is very low at 1.1 mΩ, resulting in very high efficiency compared to using a current shunt solution with a 5, 10, or even 50 mΩ resistor in the current path. The ACS726 is Underwriters Laboratory certified as meeting the requirements for UL 1577, and has a 60 second dielectric withstand voltage of 2100 V RMS which translates into a basic isolation working voltage of 277 V RMS. Since this package has no integrated core there is nearly zero magnetic hysteresis. Finally, the ACS726 runs off a single 3.3 V supply for easy integration into the customers' existing circuit.