Texas Instruments INA281B5IDBVT

Overview

INA281B5IDBVT from Texas Instruments is a high-precision, unidirectional current-sense amplifier with 500 V/V fixed gain, −4 V to +110 V common-mode input range, 1.3 MHz bandwidth, and ±15 µV typical input offset voltage. It operates from 2.7 V to 20 V supply and delivers 2.5 V/µs slew rate for fast overcurrent detection in 48-V server power supplies.

For engineers reviewing the INA281B5IDBVT datasheet, INA281B5IDBVT pinout, INA281B5IDBVT application, or INA281B5IDBVT equivalent, this device supports high-speed, high-common-mode current monitoring where precision at low V_SENSE (down to 8 mV full-scale) and minimal temperature drift (±0.1 µV/°C offset drift) are critical for shunt-based measurement integrity.

Technical Context

The INA281B5IDBVT uses a transconductance architecture with current-feedback amplifier topology, enabling 20 µA typical input bias current even at 110 V common-mode voltage. Its zero-drift input stage ensures stable offset performance across −40 °C to +125 °C.

This variant implements a fixed 500 V/V gain via precision internal resistor network (R₁ = 2 kΩ, R_L = 1000 kΩ), delivering 900 kHz bandwidth at 8 mV differential input and maintaining 120 dB DC CMRR with 65 dB AC CMRR at 50 kHz.

Key Specifications

Pinout & Package

SOT-23 (DBV) 5-pin package, 2.90 mm × 1.60 mm body size, optimized for space-constrained PCB layouts in power modules and baseband units.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA281B5IDBVT, INA240A5IDR offers tighter offset but sacrifices −4 V capability needed for half-bridge recirculation, while MAX40056ASA+T adds fault signaling at the cost of common-mode range-neither provides the combination of sub-ground sensing, 120 dB DC CMRR, and 48-V telecom-grade reliability.

Availability

INA281B5IDBVT 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) beamformer supervision requiring stable component supply across extended temperature and high-reliability deployments.

Supply support for INA281B5IDBVT 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 specializing in analog and embedded processing technologies, with leadership in precision signal conditioning and power management ICs.

The INA281 family is designed for high-accuracy, high-bandwidth current sensing in telecom infrastructure, server PSUs, and industrial power systems-specifically addressing the need for wide common-mode range, low drift, and fast transient response in harsh electrical environments.

FAQ

What is the maximum differential input voltage supported by the INA281B5IDBVT?

The INA281B5IDBVT supports a maximum differential input voltage of ±6 V, as specified in Absolute Maximum Ratings for the INA281A5/INA281B5 variants. This limit ensures safe operation when measuring across shunts under fault conditions, and aligns with its 500 V/V gain to prevent output saturation beyond the supply rails. Exceeding ±6 V risks permanent damage to the input stage.

Does the INA281B5IDBVT support bidirectional current sensing?

No, the INA281B5IDBVT operates in unidirectional mode only, as confirmed in the Functional Modes section of the datasheet. It measures current flowing from power supply to load and cannot accurately resolve reverse or recirculating current polarity. For bidirectional applications, TI recommends the INA229 or similar devices with dual-supply or rail-to-rail output architecture.

What is the recommended minimum load capacitance for stable operation of the INA281B5IDBVT?

The INA281B5IDBVT is stable with capacitive loads up to 500 pF without isolation resistors, as verified in Electrical Characteristics. No minimum load capacitance is required-operation with purely resistive loads (e.g., 10 kΩ to ADC input) is fully supported. Adding >500 pF capacitance may cause peaking or oscillation unless compensated per Layout Guidelines Section 9.

How does the INA281B5IDBVT handle common-mode transients, such as those from switching MOSFETs?

The INA281B5IDBVT maintains 65 dB AC CMRR at 50 kHz and exhibits fast transient rejection, demonstrated in Figure 5-23 (common-mode fast transient pulse response). Its current-feedback architecture minimizes settling delay, allowing accurate current measurement even during rapid V_CM edges typical in synchronous buck converters or Class-D amplifiers.

Can the INA281B5IDBVT be used with a 3.3-V supply?

Yes, the INA281B5IDBVT operates from 2.7 V to 20 V, so 3.3 V is within its Recommended Operating Conditions. At 3.3 V, output swing is limited to GND + 5 mV and VS − 150 mV (i.e., ~3.15 V max), and full-scale V_SENSE reduces to ~6.3 mV for 4 V output-still sufficient for precision 48-V PSU monitoring with appropriate shunt selection.