Texas Instruments INA281B1IDBVT

Overview

INA281B1IDBVT from Texas Instruments is a precision current-sense amplifier designed for unidirectional high-side or low-side shunt monitoring in industrial and telecom power systems. It operates over a –4 V to +110 V common-mode range, delivers 20 V/V fixed gain with ±0.5% max gain error, ±55 µV typical offset voltage, 1.3 MHz bandwidth, and 2.5 V/µs slew rate-enabling fast overcurrent detection in 48-V server PSUs and macro RRU power stages.

For engineers reviewing the INA281B1IDBVT datasheet, INA281B1IDBVT pinout, INA281B1IDBVT application, or INA281B1IDBVT equivalent, this page provides verified technical context, validated pin functions, confirmed operating limits (–40°C to +125°C), real-world application mappings, and two rigorously cross-checked alternative parts for current-sense amplifier selection in high-CMRR, high-bandwidth designs.

Technical Context

The INA281B1IDBVT uses a transconductance architecture with current-feedback amplification to achieve 20 µA typical input bias current at 110 V common-mode voltage and maintain 120 dB DC CMRR across –40°C to +125°C. Its zero-drift topology ensures ±0.1 µV/°C offset drift and supports accurate low-VSENSE measurement down to 10 mV full-scale.

It operates from a single 2.7 V to 20 V supply, draws 1.5 mA quiescent current, and delivers rail-to-rail output swing (to GND + 5 mV and VS – 150 mV) while sustaining stable operation with up to 500 pF capacitive load-making it suitable for direct interface with ADCs or comparator inputs in fast-response protection circuits.

Key Specifications

Pinout & Package

The INA281B1IDBVT is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for space-constrained PCB layouts in telecom and server power modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA281B1IDBVT, INA240A1IDR offers higher bandwidth but requires more board space and lacks negative common-mode support, while MAX40056ASA+T matches the SOT-23 footprint and extends survival voltage but sacrifices DC precision and CMRR-making INA281B1IDBVT optimal for compact, high-accuracy 48-V telecom and server monitoring.

Availability

INA281B1IDBVT is available at Aetrix Electronics and suitable for 48-V rack server power monitoring, macro remote radio unit (RRU) current protection, and active antenna system (AAS) per-channel feedback requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for INA281B1IDBVT 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 leader specializing in analog and embedded processing technologies, with decades of expertise in precision signal conditioning and power management ICs.

The INA281 family is engineered for high-accuracy, high-bandwidth current sensing in telecom infrastructure, enterprise servers, and industrial motor control-delivering robust performance across extreme common-mode voltages and wide temperature ranges.

FAQ

What is the maximum common-mode voltage the INA281B1IDBVT can handle during normal operation?

The INA281B1IDBVT supports a continuous operational common-mode input range of –4 V to +110 V. This allows it to function reliably in high-side configurations on 48-V or 60-V rails and tolerate negative excursions down to –4 V-critical for half-bridge recirculation current measurement. Its survival rating extends to –20 V to +120 V, providing margin against transient overvoltage events without latch-up or damage.

Does the INA281B1IDBVT support bidirectional current sensing?

No, the INA281B1IDBVT operates in unidirectional mode only-it measures current flowing from power supply to load, not reverse current. Its functional block diagram and datasheet specify linear operation only for positive differential input (VIN+ > VIN−). For bidirectional applications, TI recommends the INA229 or INA240 families, which include dedicated zero-input reference and symmetric output swing.

What is the output voltage swing capability of the INA281B1IDBVT at 5 V supply?

At VS = 5 V, the INA281B1IDBVT output swings from GND + 5 mV (typical) to VS – 150 mV (typical), delivering a usable 4.85-V output range. This rail-to-rail behavior enables direct connection to 12-bit or 16-bit SAR ADCs without external level-shifting, and the low headroom requirement simplifies power domain interfacing in mixed-voltage systems.

How does the gain option of the INA281B1IDBVT differ from the INA281A1IDBVT?

Both INA281B1IDBVT and INA281A1IDBVT provide identical 20 V/V gain, accuracy, bandwidth, and electrical specifications. The 'A' and 'B' suffixes denote different pinouts in the same SOT-23-5 (DBV) package: INA281A uses pin 3 for IN+, pin 4 for IN−, and pin 5 for VS, whereas INA281B uses pin 3 for VS, pin 4 for IN+, and pin 5 for IN−. Layout compatibility must be verified per variant.

Can the INA281B1IDBVT drive a 10-kΩ load while maintaining specified accuracy?

Yes-the INA281B1IDBVT is characterized for R_LOAD = 10 kΩ in its electrical specifications, including output swing, gain error, and settling time. Its output stage is designed to drive standard ADC input impedances and comparator thresholds without gain degradation or phase shift. Driving lower-impedance loads (<1 kΩ) may reduce output swing and increase settling time, requiring verification per application.