1 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

2 Applications
• Active antenna system mMIMO (AAS)
• Macro remote radio unit (RRU)
• 48-V rack server
• 48-V merchant network & server power supply
(PSU)
• Solenoid control
• Valve control
• Telecom equipment
• Power supplies

3 Description
The INA281-Q1 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-Q1 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-Q1 operates from a single 2.7-V to 20-
V supply, drawing 1.5 mA of supply current. The
INA281-Q1 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 currentsensing
applications.
The INA281-Q1 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.