Amplifier ICs

INA2181

INA2181 - 26V Dual-Channel Current Sense Amp | Texas Instruments

The Texas Instruments INA2181 is a 26V, dual-channel, bi-directional, 350kHz voltage-output current sense amplifier designed for cost-optimized low- and high-side current sensing. It integrates two independent current-sense amplifier channels in a single 10-pin VSSOP or WSON package, each providing a voltage output proportional to the voltage drop across an external shunt resistor. A current sense amplifier (also called a current-shunt monitor) is a specialized difference amplifier that extracts a small differential voltage developed across a shunt resistor riding on a large common-mode voltage, and translates it to a ground-referenced output. Within the power-management IC hierarchy, current sense amplifiers sit alongside fuel gauges and monitors as essential building blocks of power supervision, telemetry, and protection subsystems. Key features include a wide input common-mode range of -0.2V to 26V independent of the supply voltage, four factory-calibrated gain options (A1 = 20 V/V, A2 = 50 V/V, A3 = 100 V/V, A4 = 200 V/V), and a 350kHz bandwidth that supports fast transient monitoring and cycle-by-cycle current protection. A shared reference (REF) pin allows bi-directional current measurement by offsetting the output for both charging and discharging directions. The device operates from a 2.7V to 5.5V supply over an extended temperature range of -40C to +125C. Architecturally, the INA2181 belongs to the INA181 (INAx181) family, which also includes the single-channel INA181 (SOT-23/SC70) and quad-channel INA4181 (TSSOP-20). This dual-channel integration halves solution size and cost in applications that monitor two rails or both ends of a battery. Typical applications include battery charging and discharging monitoring, power supply and DC-DC converter current telemetry, motor control current feedback, load management, and industrial automation. The 350kHz bandwidth and fast 1us settling make it suitable for peak-current limit implementations in power converters. When designing, select the shunt resistor so the full-scale shunt voltage stays within the 10mV-to-100mV optimal range for your gain option, and use a Kelvin (4-wire) connection to the shunt to preserve accuracy. The REF pin must be driven from a low-impedance source to avoid gain error.