Texas Instruments INA139NA/250

Overview

INA139NA/250 from Texas Instruments is a high-side, unipolar current shunt monitor IC in 5-pin SOT-23 package, delivering 1000 µA/V transconductance, ±1.5 mV input offset voltage (max), and 440 kHz bandwidth with 10 kΩ load. It operates from 2.7 V to 40 V supply and supports up to 40 V common-mode input voltage, enabling precise current sensing in automotive power rails and battery management systems.

For engineers reviewing the INA139NA/250 datasheet, INA139NA/250 pinout, INA139NA/250 application, or INA139NA/250 equivalent, key selection considerations include its current-output architecture requiring external RL for gain setting, –40°C to +125°C operating range, 60 µA quiescent current, and compatibility with high-side shunt placements where VIN+ exceeds V+.

Technical Context

The INA139NA/250 integrates a precision op amp, laser-trimmed thin-film resistors, and a low-noise output transistor to convert differential shunt voltage (up to 500 mV) into a proportional output current. Its input common-mode and supply voltages are fully independent-VIN+ can reach 40 V while V+ remains as low as 2.7 V.

This architecture enables true high-side sensing without level-shifting circuitry: the device maintains 99 dB minimum CMRR across 10 Hz–100 kHz and delivers <±0.13% nonlinearity error over 10–150 mV input range, with output compliance governed by both V+ and VIN+ limits.

Key Specifications

Pinout & Package

INA139NA/250 is housed in a 5-pin SOT-23 (DBV) package measuring 2.90 mm × 1.60 mm, optimized for space-constrained PCB layouts in power management modules.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-side current measurement applications.

Compared with INA139NA/250, INA169NA/3K extends common-mode capability at the cost of temperature range, while MAX4080TASA+ trades configurability and CMRR for integration and package size-making INA139NA/250 optimal for compact, high-accuracy, wide-temperature high-side sensing.

Availability

INA139NA/250 is available at Aetrix Electronics and suitable for automotive power rail monitoring, battery management systems, and industrial DC power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for INA139NA/250 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 precision amplifiers, data converters, and power management ICs.

The INA1x9 product line was designed specifically for high-side current sensing in harsh environments-delivering robust performance across automotive, industrial, and telecom power systems where accuracy, temperature resilience, and supply independence are critical.

FAQ

What is the maximum input common-mode voltage supported by the INA139NA/250?

The INA139NA/250 supports an input common-mode voltage range of 2.7 V to 40 V. This means VIN+ can be as high as 40 V while V+ remains at its minimum 2.7 V, enabling direct high-side sensing on 36-V automotive buses or industrial power rails without attenuation or level shifting. The absolute maximum rating is 60 V, but operation above 40 V is outside specified performance limits.

How does the INA139NA/250 generate its output signal?

The INA139NA/250 outputs a current-not a voltage-proportional to the differential input voltage: I_OUT = 1000 µA/V × (VIN+ − VIN−). This current must be converted to a measurable voltage using an external load resistor (RL) connected from OUT to ground. For example, with RL = 10 kΩ and 100 mV across the shunt, INA139NA/250 delivers 100 µA, producing 1.0 V at the OUT pin.

Can the INA139NA/250 measure bidirectional current?

No-the INA139NA/250 is a unipolar device intended for single-direction current measurement. Its input stage saturates if VIN− exceeds VIN+, resulting in zero output current. To measure bidirectional current, two INA139NA/250 devices must be used-one across the shunt in each polarity-with external logic (e.g., comparator) to determine direction, as shown in TI's Figure 15 application circuit.

What is the recommended value for the external load resistor RL in the INA139NA/250 circuit?

RL values from 1 kΩ to 100 kΩ are supported, with optimal trade-offs between gain, bandwidth, and noise. For 5 V full-scale output with 500 mV max input, RL = 10 kΩ is standard. Higher RL increases gain but reduces bandwidth (e.g., 20 kΩ → 220 kHz); lower RL improves speed but reduces signal-to-noise ratio. RL must be ≥1 kΩ to ensure stability and avoid excessive output loading.

Does the INA139NA/250 require a separate ground connection for the shunt resistor?

Yes-the INA139NA/250 requires a dedicated analog ground (Pin 2) tied to the same low-impedance ground plane as the shunt resistor's low-side terminal (VIN−). This prevents ground loop errors and preserves CMRR. The device's GND pin must not share traces with digital or power grounds; star grounding near the shunt is strongly recommended to maintain ±0.5% total output error.