Texas Instruments INA241B1QDDFRQ1

Overview

INA241B1QDDFRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive-qualified, bidirectional current sense amplifier with 10V/V gain, −5V to 110V common-mode input range, ±150µV max input offset voltage, and 1.1MHz bandwidth-designed for high-precision motor phase current monitoring in electric power steering (EPS) systems.

For engineers reviewing the INA241B1QDDFRQ1 datasheet, INA241B1QDDFRQ1 pinout, INA241B1QDDFRQ1 application, or INA241B1QDDFRQ1 equivalent, key selection criteria include PWM rejection up to 125kHz, 8V/µs slew rate, 1µs 1% settling time, and SOT-23-8 package compatibility with space-constrained automotive control modules.

Technical Context

The INA241B1QDDFRQ1 implements a zero-drift, high-side/low-side/bidirectional topology with enhanced PWM rejection circuitry that holds output for 1µs during large ΔV/Δt common-mode transients-enabling accurate current measurement under fast-switching conditions in inverter-driven motors. Its input stage operates independently of supply voltage, supporting common-mode voltages beyond VS (up to 110V).

It features dual reference inputs (REF1/REF2) enabling flexible output level shifting between 0V and VS, and maintains 120–130dB AC-CMRR at 100kHz while delivering 10V/V fixed gain with ±0.1% max gain error and ±5ppm/°C drift across −40°C to 125°C.

Key Specifications

Pinout & Package

INA241B1QDDFRQ1 uses the DDF (SOT-23-8) package: 2.9mm × 2.8mm, 8-pin surface-mount, thermally enhanced with exposed pad (not electrically connected). Pin 1 = IN−, Pin 2 = GND, Pin 3 = REF2, Pin 4 = NC (connect to GND), Pin 5 = OUT, Pin 6 = VS, Pin 7 = REF1, Pin 8 = IN+.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA241B1QDDFRQ1, INA240A1QDDFRQ1 trades PWM rejection for lower offset, while MAX40056ATA+T offers lower cost but sacrifices automotive qualification, bandwidth, and common-mode range-making INA241B1QDDFRQ1 the sole option meeting full AEC-Q100 Grade 1, 125kHz PWM rejection, and 110V common-mode requirements.

Availability

INA241B1QDDFRQ1 is available at Aetrix Electronics and suitable for electric power steering (EPS), eTurbo control, starter/generator, and regenerative braking systems requiring stable component supply, long-term automotive lifecycle support, and AEC-Q100-compliant traceability.

Supply support for INA241B1QDDFRQ1 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 automotive-grade signal conditioning and power management solutions.

The INA241x-Q1 product line was developed specifically for high-precision, high-reliability current sensing in automotive electrification systems-including EPS, eAxles, and 48V mild hybrids-where PWM noise immunity and extended common-mode range are mandatory.

FAQ

What is the maximum common-mode voltage the INA241B1QDDFRQ1 can withstand during normal operation?

The INA241B1QDDFRQ1 operates over a common-mode input range of −5V to 110V under recommended conditions. Its survival rating extends to −20V to 120V, allowing tolerance of short-duration transients such as load dump or inductive kickback without damage-critical for robust deployment in 48V automotive systems where bus voltages may spike beyond nominal levels during fault conditions. This specification is validated per AEC-Q100 stress testing protocols.

Does the INA241B1QDDFRQ1 support bidirectional current sensing, and how is direction determined?

Yes, the INA241B1QDDFRQ1 supports true bidirectional current sensing. Direction is determined by the polarity of the differential voltage (V_IN+ − V_IN−) across the shunt resistor: positive voltage indicates current flow toward the load (motoring), negative voltage indicates reverse flow (regeneration). The output voltage scales linearly as V_OUT = 10 × (V_IN+ − V_IN−) + V_REF, where V_REF is set by REF1/REF2 pins-enabling zero-centered output for symmetric positive/negative current ranges.

What is the purpose of the REF1 and REF2 pins on the INA241B1QDDFRQ1, and how should they be configured?

The REF1 and REF2 pins on the INA241B1QDDFRQ1 set the output common-mode voltage via an internal resistive divider. Connecting REF1 to VS and REF2 to GND configures V_OUT = 10 × (V_IN+ − V_IN−) + 0.5 × VS, centering the output at mid-supply for optimal ADC utilization. Alternative configurations (e.g., both tied to GND) yield unipolar output referenced to ground. This flexibility allows seamless interfacing with single-supply or differential-input ADCs without external level-shifting circuitry-reducing design complexity and component count in automotive ECUs.

How does the enhanced PWM rejection feature of the INA241B1QDDFRQ1 improve system performance in motor drive applications?

The enhanced PWM rejection feature in the INA241B1QDDFRQ1 minimizes output disturbance during fast common-mode transients-such as those generated by SiC MOSFET switching in motor inverters-by holding the output stable for 1µs after each edge and leveraging >104dB AC-CMRR at 100kHz. This eliminates false overcurrent triggers and preserves measurement fidelity during PWM dead-time and commutation events, enabling tighter current-loop bandwidth and improved torque control accuracy in EPS and eTurbo systems without requiring additional RC filtering or digital post-processing.

Is the INA241B1QDDFRQ1 pin-compatible with other members of the INA241x-Q1 family, such as the INA241A1QDDFRQ1?

Yes, the INA241B1QDDFRQ1 is pin-compatible with all SOT-23-8 variants in the INA241x-Q1 family-including INA241A1QDDFRQ1-sharing identical pinout, package dimensions, and reference interface. The primary difference lies in precision grade: INA241B1QDDFRQ1 offers ±150µV max offset and ±0.1% max gain error, while INA241A1QDDFRQ1 delivers ±10µV offset and ±0.01% gain error. Both maintain identical electrical timing, thermal, and layout requirements-allowing drop-in replacement for cost/performance trade-offs without PCB redesign.