INA281/INA281-Q1 Current Sense Amplifier Texas Instruments INA281/INA281-Q1 Current Sense Amplifier can measure voltage drops across shunt resistors over a wide common-mode range from –4V to 110V. The negative common-mode voltage allows the device to operate below ground, thus accommodating precise measurement of recirculating currents in half-bridge applications. The combination of a low offset voltage, small gain error, and high DC CMRR enables highly accurate current measurement. The Texas Instruments INA281/INA281-Q1 is not only designed for DC current measurement but also high-speed applications (like fast over current protection, for example) with high bandwidth of 1.3MHz and a 65dB AC CMRR (at 50kHz).