描述 Description

The INA281 is a high-precision current sense amplifier that can measure voltage drops across shunt resistors over a wide common-mode range from –4 V to 110 V. 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 INA281 is not only designed for DC current measurement, but also for high-speed applications (like fast overcurrent protection, for example) with a high bandwidth of 1.3 MHz and an 65-dB AC CMRR (at 50 kHz).

The INA281 operates from a single 2.7-V to 20-V supply, drawing 1.5 mA of supply current. The INA281 is available with five gain options: 20 V/V, 50 V/V, 100 V/V, 200 V/V, and 500 V/V. These gain options address wide dynamic range for current-sensing applications.

The INA281 is specified over an operating temperature range of ?40 °C to +125 °C and is offered in a space-saving SOT-23 package with two pin-out variants.

特性 Features

? Wide common-mode voltage:
? Operational voltage: ?4 V to +110 V
? Survival voltage: ?20 V to +120 V

? Excellent CMRR:
? 120-dB DC CMRR
? 65-dB AC CMRR at 50 kHz

? Accuracy:
? Gain:
? Gain error: ±0.5% (maximum)
? Gain drift: ±20 ppm/°C (maximum)

? Offset:
? Offset voltage: ±55 μV (typical)
? Offset drift: ±0.1 μV/°C (typical)


? Available gains:
? INA281A1, INA281B1 : 20 V/V
? INA281A2, INA281B2 : 50 V/V
? INA281A3, INA281B3 : 100 V/V
? INA281A4, INA281B4 : 200 V/V
? INA281A5, INA281B5 : 500 V/V

? High bandwidth: 1.3 MHz
? Slew rate: 2.5V/μs
? Quiescent current: 1.5 mA