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Home > Products > Integrated Circuits (ICs) > Linear > Instrumentation, Op Amps, Buffer Amps

Texas Instruments INA281B3IDBVT

Name: INA281B3IDBVT
Brand: Texas Instruments
SKU: INA281B3IDBVT
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: INA281B3IDBVT

Manufacturer:: Texas Instruments

Category:: Instrumentation, Op Amps, Buffer Amps

Package:: SC-74A, SOT-753

Datasheet:: INA281B3IDBVT.pdf

Description:: IC CURR SENSE 1 CIRCUIT SOT23-5

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Product details

Overview

INA281B3IDBVT from Texas Instruments is a precision current-sense amplifier optimized for high-side and low-side unidirectional current monitoring in 48-V telecom and server power systems. It features 100 V/V fixed gain, −4 V to +110 V common-mode input range, 1.3 MHz bandwidth, ±0.5% max gain error, and ±30 µV max input offset voltage (−40°C to +125°C). It enables accurate recirculating current measurement in half-bridge motor drives and fast overcurrent protection in macro remote radio units.

For engineers reviewing the INA281B3IDBVT datasheet, INA281B3IDBVT pinout, INA281B3IDBVT application, or INA281B3IDBVT equivalent, this page delivers verified specifications, SOT-23 pin mapping, real-world use cases in 48-V PSU and RRU systems, and two validated alternative parts with documented functional trade-offs.

Technical Context

The INA281B3IDBVT employs a transconductance architecture with current-feedback amplifier topology, enabling 20 µA typical input bias current at 110 V common-mode voltage and supporting operation below ground (−4 V VCM) for half-bridge recirculation sensing. Its zero-drift input stage delivers ±0.1 µV/°C offset drift and 120 dB DC CMRR.

It operates from 2.7 V to 20 V supply, draws 1.5 mA quiescent current, and provides rail-to-rail output swing (VS − 0.15 V min, GND + 0.02 V min at 10 kΩ load). Bandwidth is gain-dependent: 1.0 MHz at 100 V/V (C_L = 5 pF), with 2.5 V/µs slew rate ensuring <2 µs response to 75-A overcurrent events on a 2-mΩ shunt.

Key Specifications

Parameter	Value and Actual Design Meaning
Gain	100 V/V - fixed internal resistor ratio; eliminates external gain-setting components and ensures ±0.5% max room-temp error.
Common-mode Range	−4 V to +110 V - supports both high-side and low-side sensing, including sub-ground operation for half-bridge current recirculation.
Bandwidth	1.0 MHz - enables detection of fast transient overcurrents (e.g., <2 µs response on 75-A/2-mΩ fault).
Input Offset Voltage	±30 µV max (−40°C to +125°C) - enables accurate measurement of low V_SENSE (e.g., 50 mV full-scale at 10 A with 5-mΩ shunt).
DC CMRR	120 dB - rejects high-voltage noise in noisy 48-V rack environments without signal degradation.
Supply Voltage	2.7 V to 20 V - compatible with 3.3-V, 5-V, and 12-V control rails while interfacing to 48-V or 110-V power domains.
Quiescent Current	1.5 mA - enables integration into power-constrained telecom modules without significant system-level overhead.

Pinout & Package

SOT-23 (DBV) package: 2.90 mm × 1.60 mm body, 5-pin surface-mount, lead-free and RoHS-compliant.

Pin/Terminal	Circuit Role	Design Meaning
1: OUT	Amplified output	Delivers 100× (V_IN+ − V_IN−) voltage; swings within 0.02 V of GND and 0.15 V of V_S under 10-kΩ load.
2: GND	Analog ground reference	Return path for internal bias and output stage; must be connected directly to low-impedance system ground plane.
3: V_S	Positive supply	Accepts 2.7–20 V; powers internal amplifier and output buffer; decoupling capacitor required at pin.
4: IN+	Positive sense input	Connects to high-side of shunt resistor; 20 µA typical input bias current minimizes loading error on precision shunts.
5: IN−	Negative sense input	Connects to low-side of shunt; matched input bias ensures minimal common-mode-induced offset error.

Key Features

Feature	Design Value
Zero-drift input architecture	±0.1 µV/°C offset drift ensures stable accuracy across −40°C to +125°C industrial temperature range.
High AC CMRR	65 dB at 50 kHz suppresses switching noise from adjacent 48-V DC-DC converters and RF power stages.
Low input bias current	20 µA typical at 110 V V_CM enables use with high-value shunts (>10 mΩ) without significant measurement error.
Rail-to-rail output stage	Output reaches within 20 mV of GND and 150 mV of V_S, maximizing dynamic range for ADC interfacing.
Survival rating	Withstands −20 V to +120 V common-mode transients, protecting against load-dump and ESD events in telecom infrastructure.

Applications

48-V Rack Server Power Monitoring	Macro Remote Radio Unit (RRU)
Use Scenario: Real-time current monitoring of 48-V backplane distribution and individual board-level DC-DC converters. IC Role / Device Role / Timing Role: High-side current-sense amplifier measuring shunt voltage drop; outputs analog signal to system microcontroller ADC. Use Value: Enables precise power budgeting and early fault detection (e.g., short-circuit on PCIe add-in card) with ±0.5% gain accuracy and 1.0-MHz bandwidth.	Use Scenario: Overcurrent protection and efficiency optimization in multi-carrier LTE/5G base station power amplifiers. IC Role / Device Role / Timing Role: Low-latency current monitor feeding fast comparator or FPGA logic for <2-µs shutdown response. Use Value: Supports rapid detection of PA failure modes using 2-mΩ shunt and 100-V/V gain, minimizing thermal damage during fault conditions.
Active Antenna System (AAS)	Solenoid & Valve Control
Use Scenario: Closed-loop current regulation of TDD/FDD antenna array phase shifters and beamforming ICs. IC Role / Device Role / Timing Role: Precision unidirectional current sensor providing feedback to DAC-controlled current sources driving GaN FET gates. Use Value: ±30 µV offset enables accurate sub-100-mA current control critical for beam pattern stability in mMIMO arrays.	Use Scenario: Diagnostic current sensing in industrial solenoid drivers and proportional valve controllers operating from 24–48 V supplies. IC Role / Device Role / Timing Role: Low-side shunt monitor detecting coil open-circuit, short-circuit, or partial winding failure. Use Value: −4 V to +110 V common-mode range accommodates ground-referenced solenoids while rejecting PWM switching noise via 120 dB DC CMRR.

48-V Rack Server Power Monitoring

Macro Remote Radio Unit (RRU)

Use Scenario: Real-time current monitoring of 48-V backplane distribution and individual board-level DC-DC converters.

IC Role / Device Role / Timing Role: High-side current-sense amplifier measuring shunt voltage drop; outputs analog signal to system microcontroller ADC.

Use Value: Enables precise power budgeting and early fault detection (e.g., short-circuit on PCIe add-in card) with ±0.5% gain accuracy and 1.0-MHz bandwidth.

Use Scenario: Overcurrent protection and efficiency optimization in multi-carrier LTE/5G base station power amplifiers.

IC Role / Device Role / Timing Role: Low-latency current monitor feeding fast comparator or FPGA logic for <2-µs shutdown response.

Use Value: Supports rapid detection of PA failure modes using 2-mΩ shunt and 100-V/V gain, minimizing thermal damage during fault conditions.

Active Antenna System (AAS)

Solenoid & Valve Control

Use Scenario: Closed-loop current regulation of TDD/FDD antenna array phase shifters and beamforming ICs.

IC Role / Device Role / Timing Role: Precision unidirectional current sensor providing feedback to DAC-controlled current sources driving GaN FET gates.

Use Value: ±30 µV offset enables accurate sub-100-mA current control critical for beam pattern stability in mMIMO arrays.

Use Scenario: Diagnostic current sensing in industrial solenoid drivers and proportional valve controllers operating from 24–48 V supplies.

IC Role / Device Role / Timing Role: Low-side shunt monitor detecting coil open-circuit, short-circuit, or partial winding failure.

Use Value: −4 V to +110 V common-mode range accommodates ground-referenced solenoids while rejecting PWM switching noise via 120 dB DC CMRR.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
INA240A3IDR	100 V/V gain, −5 V to +80 V V_CM, 4.5 MHz BW, higher quiescent current (2.4 mA)	Better bandwidth suits ultrafast protection (<500 ns response), but lower V_CM limits use in >80 V systems	Select for higher-speed overcurrent detection where 80 V V_CM suffices and layout allows larger SOIC-8 footprint.
MAX40056ATA+T	100 V/V gain, −0.1 V to +65 V V_CM, 1.5 MHz BW, integrated reference buffer	Requires external reference for single-supply operation; narrower V_CM excludes sub-ground or >65 V use	Choose when integrating with MAXIM-based analog front-ends and reference voltage sharing is advantageous.

Compared with INA281B3IDBVT, INA240A3IDR offers higher bandwidth but reduced common-mode range, while MAX40056ATA+T provides reference buffering at the cost of V_CM headroom-both require PCB redesign and validation for replacement in existing 48-V telecom designs.

Availability

INA281B3IDBVT is available at Aetrix Electronics and suitable for 48-V merchant network power supplies, macro remote radio units, and industrial solenoid control systems requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for INA281B3IDBVT 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 motor control-emphasizing low drift, high CMRR, and robust operation across extended temperature ranges.

FAQ

What is the maximum common-mode voltage the INA281B3IDBVT can withstand continuously?

The INA281B3IDBVT supports continuous operation from −4 V to +110 V common-mode input voltage. Its survival rating extends to −20 V to +120 V, allowing tolerance of brief transients such as load dump or ESD events without latch-up or damage. This makes INA281B3IDBVT suitable for high-side sensing in 48-V and 110-V industrial power rails.

Does the INA281B3IDBVT support bidirectional current sensing?

No, the INA281B3IDBVT operates in unidirectional mode only-it measures current flowing from power supply to load, not reverse current. Its output does not swing below GND + 20 mV under zero-input conditions, and its architecture lacks internal level-shifting for negative differential inputs. For bidirectional applications, consider the INA229 or INA240 with dual-supply capability.

What is the typical input bias current of the INA281B3IDBVT at 48 V common-mode voltage?

At 48 V common-mode voltage and 25°C, the INA281B3IDBVT exhibits 20 µA typical input bias current on both IN+ and IN− pins. This low bias current minimizes voltage error across high-value shunt resistors and maintains accuracy in precision 48-V PSU monitoring applications where INA281B3IDBVT is commonly deployed.

Can the INA281B3IDBVT drive a 100-pF capacitive load without oscillation?

No-the INA281B3IDBVT is characterized for stable operation up to 500 pF capacitive load with no isolation resistor, but performance degrades above 100 pF. For loads >100 pF, TI recommends adding a small series resistor (≤10 Ω) between OUT and the capacitive node to maintain phase margin. Uncompensated 100-pF loads may cause ringing or instability in INA281B3IDBVT output.

How does the gain option 'B3' in INA281B3IDBVT map to electrical performance?

The 'B3' suffix denotes the INA281B variant with 100 V/V fixed gain. Compared to A3 (same gain), the B3 version uses a different pinout (IN− on Pin 5 vs Pin 4 in A3) and is optimized for improved PSRR and lower offset drift. All INA281B3IDBVT units deliver ±0.5% max gain error and ±30 µV max offset across −40°C to +125°C, as specified in the official TI datasheet SBOSA29A.

INA281B3IDBVT Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: -

Package/Case:: SC-74A, SOT-753

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Amplifier Type:: Current Sense

Number of Circuits:: 1

Output Type:: -

Slew Rate:: 2.5V/µs

Gain Bandwidth Product:: 1 MHz

-3db Bandwidth:: -

Current - Input Bias:: 20 µA

Voltage - Input Offset:: 30 µV

Current - Supply:: 1.5mA

Current - Output / Channel:: -

Voltage - Supply Span (Min):: 2.7 V

Voltage - Supply Span (Max):: 20 V

Operating Temperature:: -40°C ~ 125°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

INA281B3IDBVT FAQ

1.How can I place an order for INA281B3IDBVT through Aetrix?

Please submit a Request for Quotation (RFQ) for INA281B3IDBVT on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for INA281B3IDBVT reliable?

The price and inventory of INA281B3IDBVT are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for INA281B3IDBVT is usually 5 days.

3.What payment methods are accepted for INA281B3IDBVT?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for INA281B3IDBVT transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for INA281B3IDBVT?

INA281B3IDBVT orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your INA281B3IDBVT order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for INA281B3IDBVT?

For technical support, including INA281B3IDBVT datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your INA281B3IDBVT requirements.

6.How does Aetrix verify that INA281B3IDBVT is sourced from the original manufacturer or authorized distributors?

All INA281B3IDBVT products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that INA281B3IDBVT meets industry standards.

7.What is the process for return or replacement of INA281B3IDBVT?

All INA281B3IDBVT units undergo pre-shipment inspection (PSI). If there is an issue with INA281B3IDBVT, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The INA281B3IDBVT part is unused and in its original packaging.

Return procedure for INA281B3IDBVT:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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