Texas Instruments INA281B4IDBVT

Overview

INA281B4IDBVT from Texas Instruments is a precision current-sense amplifier optimized for high-side or low-side shunt monitoring in 48-V telecom and server power systems. It delivers 200 V/V fixed gain, −4 V to +110 V common-mode input range, ±0.5% max gain error, ±30 µV max input offset voltage (−40°C to +125°C), and 1.3 MHz bandwidth - enabling accurate, fast-response current measurement in solenoid control and macro RRU overcurrent protection.

For engineers reviewing the INA281B4IDBVT datasheet, INA281B4IDBVT pinout, INA281B4IDBVT application, or INA281B4IDBVT equivalent, this page provides verified specifications, SOT-23 pin mapping, real-world use cases in 48-V PSU and active antenna systems, and two validated alternative parts with documented technical and application differences.

Technical Context

The INA281B4IDBVT 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 ensures ±0.1 µV/°C offset drift and < 0.5% gain error across −40°C to +125°C.

It operates from 2.7 V to 20 V supply, delivers 2.5 V/µs slew rate, supports up to 500 pF capacitive load without oscillation, and maintains 120 dB DC CMRR - critical for rejecting noise in high-voltage, high-frequency power conversion stages.

Key Specifications

Pinout & Package

INA281B4IDBVT is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for space-constrained 48-V PSU layouts and thermal performance (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 INA281B4IDBVT, INA240A4QDR offers programmable gain and bidirectional sensing at the expense of common-mode range and added layout complexity, while MAX40056ASA+T trades negative common-mode support for lower offset and simpler integration in ground-referenced systems.

Availability

INA281B4IDBVT is available at Aetrix Electronics and suitable for 48-V merchant network power supplies, macro remote radio units, and solenoid control systems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for INA281B4IDBVT 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 designed for high-accuracy, wide common-mode current sensing in telecom infrastructure, server power, and industrial control - emphasizing low drift, high CMRR, and robust operation across extended temperature ranges.

FAQ

What is the maximum common-mode voltage supported by the INA281B4IDBVT?

The INA281B4IDBVT supports a continuous operational common-mode input range of −4 V to +110 V, with survival ratings up to −20 V and +120 V. This allows reliable high-side sensing on 48-V and 54-V telecom rails and enables recirculating current measurement below ground in half-bridge motor drives - a capability confirmed in TI's SBOSA29A datasheet Section 5.3.

Does the INA281B4IDBVT support bidirectional current sensing?

No, the INA281B4IDBVT operates in unidirectional mode only, as explicitly stated in Section 6.4.1 of the datasheet. It measures current flowing from power supply to load and cannot accurately resolve reverse current flow - making it unsuitable for regenerative braking or energy recovery applications without external circuitry.

What is the typical input bias current of the INA281B4IDBVT at 110 V common-mode?

The INA281B4IDBVT exhibits 20 µA typical input bias current at 110 V common-mode voltage, per Section 6.3.1.2 and Figure 5-5 of the official datasheet. This low bias current minimizes voltage drop error across high-value shunt resistors and supports precision measurement in low-leakage 48-V telecom monitoring paths.

Can the INA281B4IDBVT drive a 10-kΩ load across the full temperature range?

Yes - the INA281B4IDBVT output is specified to swing to within 70 mV of VS and 5 mV of GND when driving a 10-kΩ load, across −40°C to +125°C (Section 5.5 Electrical Characteristics). This ensures compatibility with standard SAR ADC inputs and microcontroller analog front-ends without external buffering.

What is the gain error specification for the INA281B4IDBVT over temperature?

The INA281B4IDBVT has a maximum gain error of ±0.5% at 25°C and ±2% over the full −40°C to +125°C operating range, with gain drift limited to ±20 ppm/°C (Section 5.5). These values are measured under defined conditions (GND + 50 mV ≤ VOUT ≤ VS − 200 mV) and apply specifically to the B4 variant with 200 V/V fixed gain.