SBAU461 May 2024 INA790B , INA791B
To assess whether the expected load matches the measured load, use a precision shunt resistor rated for the maximum intended current in series with the DUT. The precision shunt needs to have a kelvin connection where the generated sense voltage can be measured by a precision multimeter, such as the 3458a multimeter. Sensing an external shunt voltage is preferred, as a typical multimeter can have a current limit far below the needed current measurement limits in question. Additionally, some meters have better voltage measurement precision than current measurement precision.
For evaluating performance when the DUT is subjected to quick current pulses, use short, large-gauge wire, or short bus bars, to reduce the inductance and resistance between the HV-supply, load, and EVM. By minimizing the inductance, the rate of load slew can be increased. If assessing the performance over large transient current spikes (>20 A) is desired, then be sure to use a supply with sufficient voltage headroom to accommodate the series resistance of the wires or bus bars, the board planes, and the DUT lead frame resistance. Use a large capacitor bank between the supply terminals to make sure there is an adequate charge reservoir available to prevent the supply from drooping. A large capacitor bank can also help supply the large current inrush through the device.
To assess temperature performance, use wide, thin bus bars to reduce the thermal sinking ability of the system and minimize the inductance of the system. Board temperature are not an exact indicator of DUT temperature. More precise measurements can be obtained by placing a layer of thermally conductive grease on top of the DUT package and placing a thermal sensor directly on the thermal grease. See Thermal Implementation Guide for In-Package Magnetic Current Sensors for tips on thermal best practices.