Texas Instruments INA281B2IDBVT

Overview

INA281B2IDBVT from Texas Instruments is a precision current-sense amplifier designed for high-side or low-side shunt monitoring in industrial and telecom power systems. It delivers 50 V/V fixed gain, −4 V to +110 V common-mode input range, 1.3 MHz bandwidth, ±55 µV typical offset voltage, and operates from 2.7 V to 20 V supply. It enables accurate real-time current measurement in 48-V server PSUs and fast overcurrent protection circuits.

For engineers reviewing the INA281B2IDBVT datasheet, INA281B2IDBVT pinout, INA281B2IDBVT application, or INA281B2IDBVT equivalent, this page provides verified technical context, validated pin functions, confirmed operating parameters across temperature, and real-world implementation constraints - all specific to the INA281B2IDBVT variant in SOT-23 (DBV) package.

Technical Context

The INA281B2IDBVT uses a transconductance architecture with current-feedback amplifier topology, enabling 20 µA typical input bias current at 110 V common-mode and supporting unidirectional current sensing only. Its zero-drift input stage achieves ±0.5% max gain error and ±0.1 µV/°C offset drift over −40 °C to +125 °C.

It features a gain-dependent −3 dB bandwidth: 1.3 MHz at 50 V/V with 5 pF load and 80 mV sense voltage, and maintains 65 dB AC CMRR at 50 kHz. The output swings within 5 mV of ground and to within 7% of VS across temperature and supply voltage.

Key Specifications

Pinout & Package

SOT-23 (DBV) 5-pin package: 2.90 mm × 1.60 mm body, surface-mount, lead-free, RoHS-compliant. Thermal resistance R_θJA = 184.7 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-sense amplifier applications.

Compared with INA240A2IDR and MAX40056ASA+, the INA281B2IDBVT uniquely supports −4 V to +110 V operation with 1.3 MHz bandwidth and 50 V/V gain - making it the only option among the three qualified for 48-V telecom rack servers requiring sub-2 µs overcurrent response and true negative common-mode capability.

Availability

INA281B2IDBVT is available at Aetrix Electronics and suitable for 48-V server PSUs, macro RRU protection circuits, and solenoid control systems requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.

Supply support for INA281B2IDBVT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company delivering analog and embedded processing solutions, with leadership in precision analog, power management, and signal chain technologies.

The INA281 product line is engineered for high-accuracy, wide common-mode current sensing in industrial power supplies, telecom infrastructure, and motor control - emphasizing speed, offset stability, and robustness across harsh thermal and electrical environments.

FAQ

What is the maximum common-mode voltage the INA281B2IDBVT can withstand continuously?

The INA281B2IDBVT supports continuous operation from −4 V to +110 V common-mode voltage. Its survival rating extends to −20 V to +120 V, meaning it tolerates brief transients beyond operational limits without damage. This makes the INA281B2IDBVT suitable for high-side monitoring on 48-V and 110-V bus systems where ground-referenced measurement is impractical. All specifications in the INA281B2IDBVT datasheet are validated within the −4 V to +110 V range.

Does the INA281B2IDBVT support bidirectional current sensing?

No, the INA281B2IDBVT operates in unidirectional mode only - it measures current flowing from power supply to load, not reverse current. Its output does not swing below GND + 5 mV, so it cannot represent negative current direction. For bidirectional applications, a different device such as the INA226 or INA240 with rail-to-rail output and symmetric offset is required. The INA281B2IDBVT design intentionally optimizes for speed and precision in forward-only use cases like overcurrent protection.

What is the recommended minimum shunt resistor value for the INA281B2IDBVT at 10-A full-scale current?

For 10-A full-scale current and 50 V/V gain, the minimum recommended shunt resistor is 5 mΩ - yielding 500 mV differential input (10 A × 5 mΩ) and 25 V output (500 mV × 50), which exceeds the 20-V absolute maximum supply. Using the recommended 5-V supply, a 5-mΩ shunt gives 250 mV input and 12.5 V output - still excessive. Per TI's design example in the INA281B2IDBVT datasheet, a 10-A system with 5-V supply uses a 10-mΩ shunt (100 mV input → 5 V output). Therefore, 10 mΩ is the practical minimum for standard 5-V operation with the INA281B2IDBVT.

Can the INA281B2IDBVT be used with a 3.3-V supply?

Yes, the INA281B2IDBVT operates from 2.7 V to 20 V, so 3.3 V is fully supported. At 3.3 V, its output swings from GND + 5 mV to VS − 0.23 V (7% drop), delivering ~3.07 V maximum. With 50 V/V gain, this supports up to 61.4 mV differential input - corresponding to 12.3-A current on a 5-mΩ shunt. Quiescent current remains 1.5 mA, and all key specs (CMRR, offset, bandwidth) are characterized down to 2.7 V. System designers must verify output headroom and ADC reference alignment when using 3.3-V supply with the INA281B2IDBVT.

Is external filtering required or recommended on the IN+ and IN− pins of the INA281B2IDBVT?

No - external filtering on the IN+ and IN− pins of the INA281B2IDBVT is not required and is explicitly discouraged in the datasheet. Adding series resistors introduces gain error due to mismatched bias currents, and capacitors risk instability. If filtering is necessary, TI recommends placing it at the OUT pin instead, where the low output impedance minimizes interaction with the amplifier. Any input-side RC network must use ≤10 Ω resistors and be validated per Equation 4 and 5 in the INA281B2IDBVT datasheet to avoid degrading accuracy.