Texas Instruments INA281A3IDBVT

Overview

INA281A3IDBVT 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 100 V/V fixed gain, −4 V to +110 V common-mode input range, 1.3 MHz bandwidth, ±30 µV max input offset voltage (typical ±55 µV), 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 INA281A3IDBVT datasheet, INA281A3IDBVT pinout, INA281A3IDBVT application, or INA281A3IDBVT equivalent, this page provides verified technical context, validated pin functions, confirmed operating limits, and application-specific design meaning - all extracted from TI's official SBOSA29A datasheet revision November 2023.

Technical Context

The INA281A3IDBVT uses a transconductance architecture with current-feedback amplifier topology, enabling 20 µA typical input bias current at 110 V common-mode voltage and supporting unidirectional current sensing only. Its zero-drift input stage achieves ±0.1 µV/°C offset drift and 120-dB DC CMRR, critical for stable measurements across −40 °C to +125 °C.

Bandwidth is gain-dependent: the A3 variant (100 V/V) maintains 1.0 MHz (−3 dB) with 5 pF load and 40 mV sense input, while slew rate remains fixed at 2.5 V/µs. Output swing is rail-to-rail capable - within 70 mV of VS and 5 mV of GND under full temperature range - enabling direct interfacing with 12-bit ADCs without level-shifting.

Key Specifications

Pinout & Package

SOT-23-5 (DBV) package: compact 2.90 mm × 1.60 mm footprint with gull-wing leads, optimized for high-density PCB layouts in telecom and server applications. Thermal performance validated per JEDEC JESD51 standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA240A3IDR and MAX40056AUB+, the INA281A3IDBVT uniquely supports −4 V common-mode operation and delivers tighter offset (±30 µV max) at lower quiescent current (1.5 mA), making it optimal for high-accuracy, wide-voltage-range telecom and server power monitoring where ground-referenced recirculation currents must be measured.

Availability

INA281A3IDBVT is available at Aetrix Electronics and suitable for 48-V merchant server PSUs, macro RRU power stages, active antenna system (AAS) beamformer modules, and industrial solenoid control requiring stable component supply and long-term production continuity.

Supply support for INA281A3IDBVT 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 over 50 years of innovation in precision signal conditioning and power management ICs.

The INA281 family is engineered for high-accuracy, high-voltage current sensing in next-generation telecom infrastructure, data center power systems, and industrial automation - emphasizing wide common-mode range, low drift, and fast fault response.

FAQ

What is the maximum common-mode voltage the INA281A3IDBVT can handle during normal operation?

The INA281A3IDBVT supports a continuous common-mode input range of −4 V to +110 V under recommended operating conditions. This allows it to operate safely in high-side configurations on 48-V and 60-V rails, and even below ground for recirculating current measurement in half-bridge topologies. The device also survives transient exposures up to −20 V and +120 V without damage, as specified in absolute maximum ratings.

Does the INA281A3IDBVT support bidirectional current sensing?

No, the INA281A3IDBVT operates in unidirectional mode only - it measures current flowing from supply to load. While its −4 V common-mode capability enables sensing of negative-going shunt voltages during recirculation, the output polarity remains fixed: OUT = 100 × (V_IN+ − V_IN−). For true bidirectional measurement, a separate reference-biased amplifier or dedicated bidirectional part like the INA229 is required.

What is the typical input offset voltage of the INA281A3IDBVT, and how does it affect accuracy at low current levels?

The INA281A3IDBVT has a typical input offset voltage of ±55 µV and a maximum of ±30 µV (per datasheet Section 5.5). At 100 V/V gain, this translates to ±5.5 mV (typ) output-referred offset. When measuring low currents - e.g., 1 A across a 1-mΩ shunt (1 mV differential) - the offset contributes ~550% error. Therefore, for sub-ampere accuracy, use ≥5 mΩ shunts or apply system-level calibration to null the offset in the host controller.

Can the INA281A3IDBVT drive a capacitive load directly, and what is the maximum stable capacitance?

Yes, the INA281A3IDBVT is stable driving up to 500 pF of capacitive load without isolation resistors or external compensation. This allows direct connection to sampling ADC inputs or RC filters without risk of oscillation. For loads exceeding 500 pF, TI recommends adding a series 10-Ω resistor between OUT and the capacitor to maintain phase margin, as detailed in Section 9.1 of the SBOSA29A datasheet.

Is the INA281A3IDBVT pin-compatible with other variants in the INA281 family, such as INA281A1 or INA281A5?

Yes, all INA281x variants - including INA281A1, INA281A2, INA281A3, INA281A4, and INA281A5 - share identical SOT-23-5 (DBV) pinout and package dimensions. The only functional difference is fixed gain (20/50/100/200/500 V/V); no PCB redesign is needed when upgrading or downgrading gain within the same temperature grade and suffix (e.g., IDBVT).