INA281, –4-V to 110-V, 1.3-MHz Current-Sense Amplifier

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 current-

sensing 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.

Device Information

PART NUMBER

PACKAGE(1)

BODY SIZE (NOM)

INA281INA281-Q1

SOT-23 (5)

2.90 mm × 1.60 mm

(1)

For all available packages, see the package option

addendum at the end of the data sheet.

IN+

IN±

OUT

V

CM

-

+

Buffer

Current

Feedback

V

S

GND

RL

R1

R1

Bias

Load

R

SENSE

I

SENSE

Functional Block Diagram

INA281

SBOSA29A – JUNE 2020 – REVISED NOVEMBER 2023

An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,

intellectual property matters and other important disclaimers. PRODUCTION DATA.