Texas Instruments INA281B4QDBVRQ1

Overview

INA281B4QDBVRQ1 from Texas Instruments is an AEC-Q100 Grade 1 (–40 °C to +125 °C) unidirectional current-sense amplifier optimized for automotive high-side and low-side shunt monitoring. It delivers 200 V/V fixed gain, 1.3 MHz bandwidth, ±0.5% max gain error, ±55 µV typical input offset voltage, and operates across –4 V to +110 V common-mode range - enabling precise recirculating current measurement in half-bridge motor drivers.

For engineers reviewing the INA281B4QDBVRQ1 datasheet, INA281B4QDBVRQ1 pinout, INA281B4QDBVRQ1 application, or INA281B4QDBVRQ1 equivalent, key selection criteria include its 200 V/V gain scaling for low-V_SENSE operation (e.g., 25 mV full-scale at 10 A with 2.5 mΩ shunt), functional safety documentation support, and SOT-23-5 package compatibility with space-constrained engine control units.

Technical Context

The INA281B4QDBVRQ1 employs a transconductance architecture with current-feedback amplifier topology, enabling 20 µA typical input bias current even at 110 V common-mode voltage and supporting both high-side and low-side sensing without supply-rail dependency. Its zero-drift input stage ensures ±0.1 µV/°C offset drift and 120 dB DC CMRR for stable DC current measurement under harsh automotive thermal gradients.

With 2.5 V/µs slew rate and <2 µs response to 75-A overcurrent events on a 2-mΩ shunt, it meets fast fault-detection requirements in valve actuators and HVAC compressors. The device's 500 pF maximum capacitive load tolerance and rail-to-rail output swing (GND + 5 mV to V_S – 0.15 V) simplify interface to 3.3-V or 5-V ADCs without external level-shifting.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA281B4QDBVRQ1, INA240A4QDRQ1 trades bandwidth for programmability and lower offset, while MAX40056ATA+T offers higher bandwidth but lacks automotive qualification and wide-supply operation - making INA281B4QDBVRQ1 optimal for cost-sensitive, space-constrained AEC-Q100 systems needing guaranteed 900-kHz performance at 12-V rail.

Availability

INA281B4QDBVRQ1 is available at Aetrix Electronics and suitable for automatic transmission control, HVAC compressor monitoring, and gasoline engine platform applications requiring stable component supply across extended automotive temperature ranges and long production lifecycles.

Supply support for INA281B4QDBVRQ1 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 deep expertise in automotive-grade precision signal conditioning.

The INA281-Q1 product line delivers high-accuracy, high-bandwidth current sensing for safety-critical automotive subsystems including powertrain, chassis, and electrification - designed to meet AEC-Q100 Grade 1 and ISO 26262 functional safety requirements.

FAQ

What is the maximum common-mode voltage the INA281B4QDBVRQ1 can withstand during transient conditions?

The INA281B4QDBVRQ1 has a survival common-mode voltage rating of –20 V to +120 V, verified per AEC-Q100 stress testing. This allows it to endure automotive load-dump events (up to +120 V) and reverse-battery connections (down to –20 V) without damage, while maintaining functional operation within its operational range of –4 V to +110 V during normal use. The device remains fully specified across this survival range.

Does the INA281B4QDBVRQ1 support bidirectional current sensing?

No, the INA281B4QDBVRQ1 is a unidirectional current-sense amplifier. It measures current flowing only from the positive sense input (IN+) to the negative sense input (IN−), producing a positive output voltage proportional to that direction. For bidirectional applications such as regenerative braking monitoring, a separate device like the INA229 or INA240 with dual-supply capability is required.

What is the recommended PCB layout practice for minimizing noise coupling into the INA281B4QDBVRQ1 inputs?

Place the INA281B4QDBVRQ1 as close as possible to the shunt resistor, using Kelvin (4-wire) connections to eliminate trace resistance errors. Route IN+ and IN− traces symmetrically and tightly coupled, avoid crossing noisy power or switching nodes, and place a 100-nF ceramic decoupling capacitor between V_S and GND within 2 mm of the IC. Do not add series RC filters on the inputs unless absolutely necessary - if used, limit series resistance to ≤10 Ω to avoid gain error.

Can the INA281B4QDBVRQ1 operate from a 3.3-V supply?

Yes, the INA281B4QDBVRQ1 operates from 2.7 V to 20 V, so a 3.3-V supply is fully supported. At 3.3 V, the output swing is specified as GND + 5 mV to V_S – 0.15 V (i.e., up to 3.15 V), which interfaces directly with 3.3-V SAR ADCs. Quiescent current remains 1.5 mA, and gain error stays within ±0.5%, ensuring consistent performance across the full supply range.

How does the gain option (B4) affect the usable differential input voltage range of the INA281B4QDBVRQ1?

The B4 variant's 200 V/V gain sets the maximum usable differential input (V_SENSE) to 25 mV when operating with a 5-V supply (since V_OUT = 200 × V_SENSE ≤ 5 V – 0.15 V). This enables high-resolution current measurement with low-ohmic shunts (e.g., 2.5 mΩ at 10 A yields 25 mV), reducing power loss and thermal drift compared to lower-gain variants requiring larger shunts for the same output swing.