INA138/168 High-Side Current Shunt Monitors

Texas Instruments INA138/168 High-Side Current Shunt Monitors are high-side, unipolar, current shunt monitors. Each comes with wide input common-mode voltage range, low quiescent current, and tiny SOT-23 packaging that enables use in a variety of applications. Input common-mode and power-supply voltages are independent and can range from 2.7V to 36V for the INA138 and 2.7V to 60V for the INA168. Quiescent current is only 25µA, which permits connecting the power supply to either side of the current measurement shunt with minimal error. The device converts a differential input voltage to a current output. This current is converted back to a voltage with an external load resistor that sets any gain from 1 to over 100. Although designed for current shunt measurement, the circuit invites creative applications in measurement and level shifting.