INA791B-Q1 - 110V 75A High-Bandwidth Current Sense Amp | Texas Instruments
MPN: INA791B-Q1 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.92 | $3.92 |
| 10 | $3.52 | $35.20 |
| 100 | $2.97 | $297.00 |
| 500 | $2.46 | $1,230.00 |
| 1,000 | $2.12 | $2,120.00 |
INA791B-Q1 Overview
A current-sense amplifier is an analog IC that measures the small differential voltage developed across a shunt resistor carrying a large load current, while rejecting the large common-mode voltage present at the shunt terminals. The category belongs to the instrumentation amplifier family, itself a subclass of operational amplifiers used in measurement and protection subsystems. Current-sense amplifiers sit in the signal chain between the power stage and the MCU/ADC, enabling telemetry, overcurrent protection, and closed-loop control in DC/DC converters, motor drivers, and battery management systems.
Key features of the INA791B-Q1 include a wide -4V to +110V common-mode range, high bandwidth for fast transient response, support for 75A RMS continuous current via the integrated EZShunt resistor, and a single 2.7V to 5.5V supply drawing only 3.75 mA maximum quiescent current. The B-grade variant delivers tighter initial accuracy and lower drift than the A-grade, making it well-suited to precision telemetry across the automotive temperature range of -40C to +125C.
The architecture combines a precision chopper-stabilized front end with an EZShunt integrated shunt element, eliminating external sense resistors while maintaining high CMRR across the entire common-mode range. The device outputs an analog voltage proportional to load current that can be routed directly to an ADC input for software-based current monitoring, fault detection, and coulomb counting.
Typical applications include 48V automotive electrical systems, battery management in HEV/EV powertrains, motor control in body and chassis ECUs, solenoid and actuator monitoring, and industrial high-voltage bus telemetry. The integrated shunt simplifies PCB layout and reduces parasitic inductance that otherwise degrades high-di/dt measurement accuracy.
When designing with this part, route the high-current path directly through the integrated EZShunt pins to minimize parasitic resistance, and place a low-ESR decoupling capacitor close to the VS pin. The bidirectional capability means the output polarity indicates current direction, which simplifies charge/discharge monitoring in battery systems.
Drop-in alternatives for INA791B-Q1 — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
INA791AQWDEKRQ1
✅ Drop-In📋 Reference alternative (not in catalog)
INA791B
✅ Drop-In📋 Reference alternative (not in catalog)
INA791A
✅ Drop-In📋 Reference alternative (not in catalog)
INA791B-Q1 Maximum Ratings & Electrical Characteristics
| Product Type | Bidirectional Current-Sense Amplifier |
| Grade | B (enhanced precision vs A-grade) |
| Qualification | AEC-Q100 |
| Common-Mode Voltage Range | -4 V to +110 V |
| Continuous RMS Current (Integrated EZShunt) | 75 A |
| Supply Voltage (VS) | 2.7 V to 5.5 V |
| Quiescent Current (max) | 3.75 mA |
| Output Type | Voltage output, single-ended |
| Operating Temperature Range | -40 C to +125 C |
| Package | DFN-14 (DEK), approx. 2.5 mm x 3 mm |
| Mounting Type | Surface Mount |
| Shunt Technology | Integrated EZShunt (no external sense resistor) |
INA791B-Q1 Pin Configuration
| Pin 1 | IN+ — Positive current-sense input (integrated EZShunt high-side) |
| Pin 2 | IN+ — Positive current-sense input (integrated EZShunt high-side) |
| Pin 3 | IN- — Negative current-sense input (integrated EZShunt low-side) |
| Pin 4 | IN- — Negative current-sense input (integrated EZShunt low-side) |
| Pin 5 | IN- — Negative current-sense input (integrated EZShunt low-side) |
| Pin 6 | IN- — Negative current-sense input (integrated EZShunt low-side) |
| Pin 7 | VS — Supply voltage (2.7 V to 5.5 V) |
| Pin 8 | GND — Ground |
| Pin 9 | NC — Not connected (per datasheet) |
| Pin 10 | OUT — Analog voltage output proportional to load current |
| Pin 11 | NC — Not connected (per datasheet) |
| Pin 12 | NC — Not connected (per datasheet) |
| Pin 13 | NC — Not connected (per datasheet) |
| Pin 14 | PAD — Thermal pad (connect to GND for heat dissipation) |
Typical Applications
INA791B-Q1 is suitable for 6 applications: 48V Automotive Electrical System Monitoring, HEV/EV Battery Management Current Telemetry, Motor Control in Body and Chassis ECUs, Solenoid and Actuator Current Sensing, Industrial High-Voltage Bus Telemetry, Server and Data Center 48V Power Monitoring.
48V Automotive Electrical System Monitoring
The INA791B-Q1 fits 48V automotive rails because its -4V to +110V common-mode range covers 48V nominal plus full load-dump and reverse-battery transients, while the integrated 75A EZShunt handles peak cranking currents in mild-hybrid architectures. Placed between the 48V bus and the BMS MCU ADC input, it eliminates external shunt parasitics that otherwise corrupt fast transient readings. The B-grade precision supports tight SOC calculations required by ISO 26262 functional-safety battery monitoring. Unlike discrete shunt + op-amp solutions, the integrated EZShunt reduces PCB area by ~50% and improves measurement repeatability across the -40C to +125C automotive grade temperature range.
Recommended
HEV/EV Battery Management Current Telemetry
In HEV/EV battery packs, the INA791B-Q1's bidirectional capability enables single-IC charge and discharge current monitoring on the high-voltage pack side without polarity-switching circuitry. The 110V common-mode tolerance accommodates 400V and 800V traction pack voltages when stacked via isolated interface, while the integrated EZShunt removes the bulky discrete shunt and its thermal management burden. The B-grade offset drift is critical for accurate long-term coulomb counting during overnight EV charging sessions. Power dissipation is handled by the package thermal pad, requiring a top-side copper pour area of at least 25 mm^2 to stay within the 125C junction limit at 75A continuous.
Recommended
Motor Control in Body and Chassis ECUs
The INA791B-Q1 monitors brushed and brushless DC motor phase currents in body control modules for window lift, seat adjust, and door lock actuators, where its 75A EZShunt handles motor inrush transients directly. Fast transient response prevents false overcurrent trips during PWM edge events, while bidirectional output indicates both drive and stall currents. The AEC-Q100 qualification and -40C to +125C operating range meet under-hood and cabin ECU requirements. Compared to external-shunt designs, the integrated approach reduces PCB parasitic inductance by ~5x, improving measurement accuracy at the 20 kHz PWM frequencies typical of automotive motor drives.
Recommended
Solenoid and Actuator Current Sensing
Solenoid drivers in transmission and emissions systems benefit from the INA791B-Q1's 75A integrated EZShunt, which directly measures actuator pull-in and hold currents without the thermal derating required by discrete shunt resistors. The 110V common-mode tolerance allows the sense amplifier to sit on the high-side of 24V and 48V actuator buses. B-grade precision supports closed-loop force control in proportional solenoid valves, where small current variations translate to measurable mechanical motion. The DFN-14 package footprint (2.5 mm x 3 mm) enables placement adjacent to each solenoid output, minimizing sense-loop area and EMI susceptibility in noisy under-hood environments.
Recommended
Industrial High-Voltage Bus Telemetry
Industrial 80V-100V DC bus systems such as solar inverters, battery energy storage, and 96V telecom backup rails use the INA791B-Q1 for high-side current monitoring without external level shifters, thanks to its -4V to +110V common-mode range. The integrated EZShunt removes the BOM cost and assembly variance of external high-precision shunt resistors at 75A levels. B-grade gain error and offset drift remain tight across the -40C to +125C industrial temperature range, ensuring accurate state-of-charge and fault detection over years of service. The 3.75 mA quiescent current suits always-on telemetry nodes powered from low-current aux rails.
Recommended
Server and Data Center 48V Power Monitoring
The INA791B-Q1 monitors 48V intermediate bus currents in hyperscale data center power shelves, where its 75A EZShunt handles the full load of a single 48V-to-POL converter input. The B-grade precision enables accurate per-shelf power reporting for PUE calculations, while the AEC-Q100 qualification (a superset of industrial reliability) ensures long-term operation in continuously-running data center environments. Bidirectional sensing supports A/B bus redundancy monitoring without a second amplifier. The compact DFN-14 package fits within 1U power shelf height constraints alongside downstream buck converters, simplifying board layout versus discrete shunt solutions.
Recommended
Recommended Products Summary
Engineering reference data for INA791B-Q1 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | INA791AQWDEKRQ1 | INA791B | INA791A |
|---|---|---|---|---|
| Package | DFN-14 (DEK) | DFN-14 (DEK) - same | DFN-14 (DEK) - same | DFN-14 (DEK) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Grade / Precision | B-grade (tightest) | A-grade (relaxed) | B-grade (same) | A-grade (relaxed) |
| AEC-Q100 Qualification | Yes (-Q1 suffix) | Yes (-Q1 suffix) | No (industrial grade) | No (industrial grade) |
| Common-Mode Range | -4 V to +110 V | -4 V to +110 V | -4 V to +110 V | -4 V to +110 V |
| Integrated Shunt Current (RMS) | 75 A | 75 A | 75 A | 75 A |
| Supply Voltage (VS) | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Quiescent Current (max) | 3.75 mA | 3.75 mA | 3.75 mA | 3.75 mA |
| Operating Temperature | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C | -40 C to +125 C |
Key Differentiators
- Integrated 75 A EZShunt eliminates external sense resistor (vs INA241A-Q1)
- B-grade precision for tight SOC and telemetry accuracy (vs INA791A-Q1)
- AEC-Q100 automotive qualification with -40 C to +125 C support (vs INA791B (industrial))
Design Notes
Route the high-current path directly through the integrated EZShunt IN+ and IN- pins to minimize parasitic resistance and inductance. Place a 0.1 uF X7R decoupling capacitor within 3 mm of the VS pin and a bulk 1 uF ceramic near the supply rail. The DFN-14 thermal pad must be soldered to a top-layer copper pour of at least 25 mm^2 to maintain junction temperature below 125 C at 75 A continuous current.
Estimated: at 75 A continuous through the integrated EZShunt with typical 0.5 mOhm resistance, dissipation is approximately 2.8 W. Without adequate thermal relief, junction temperature rise above ambient will approach the 125 C limit in enclosed automotive environments. Always size copper pour to manufacturer-recommended footprint or larger and verify thermal performance with real-load bench tests before committing to production.
Keep the OUT signal trace short and routed away from the high-current EZShunt traces to avoid capacitive coupling of switching noise. Use a guard ring connected to GND around the OUT trace on PCB layers adjacent to high-current paths. Place the B-grade INA791B-Q1 close to the ADC input of the monitoring MCU to minimize ground-loop errors that degrade B-grade precision.
Compliance Information
AEC-Q100 qualified per the -Q1 suffix. RoHS and REACH compliant per TI product page. Halogen-free per TI packaging materials declaration.
