Texas Instruments INA139NA/3K

Overview

INA139NA/3K from Texas Instruments is a high-side, unipolar current shunt monitor designed for current measurement, power management, battery monitoring, portable systems, and embedded current-sensing applications. The device converts the differential voltage across an external current-sense resistor into a proportional current output, allowing designers to set the final voltage gain with an external load resistor.

As part of the TI INA139 current-shunt monitor family, INA139NA/3K supports a wide 2.7V to 40V input common-mode and supply voltage range, low quiescent current operation, and compact SOT-23-5 packaging. For engineers reviewing the INA139NA/3K datasheet, INA139NA/3K pinout, INA139NA/3K application, or INA139NA/3K equivalent, this device is widely used in battery chargers, portable electronics, power management circuits, current-source designs, and industrial current monitoring systems.

Technical Context

In embedded electronic systems, INA139NA/3K typically operates as a high-side current-sense amplifier connected across a shunt resistor placed in the positive supply path. High-side sensing allows the load to remain referenced to ground while current is monitored from the supply rail side.

The device senses the differential voltage between VIN+ and VIN− and produces an output current proportional to the measured shunt voltage. This output current is converted into a voltage by an external load resistor connected at the OUT pin, allowing flexible gain setting for different ADC input ranges, current ranges, and measurement-resolution requirements.

INA139NA/3K is commonly used in portable and battery-backup systems, battery chargers, power-management circuits, industrial controllers, motor-control monitoring circuits, communication equipment, test instruments, and embedded boards requiring compact analog current measurement.

Key Specifications

Pinout & Package

The INA139NA/3K pinout is designed for compact high-side current-sense layouts and includes differential current-sense inputs, output current pin, supply pin, and ground reference. The external shunt resistor is placed between the supply source and load, with VIN+ and VIN− connected across the sense resistor.

For PCB design, the sense-input traces should use Kelvin routing from the shunt resistor terminals to reduce resistance error and noise pickup. The OUT node should be routed carefully to the gain-setting load resistor and ADC or analog monitoring stage. A local bypass capacitor near the supply pin is recommended for stable operation, especially in systems with noisy power rails or switching loads.

Key Features

• High-side current measurement architecture supports current monitoring without interrupting ground reference paths.
• 2.7V to 40V supply and common-mode range supports a wide variety of embedded and power-management systems.
• Current output architecture allows external resistor gain setting for flexible ADC and monitoring-circuit design.
• Low typical quiescent current helps reduce power consumption in battery-powered and standby systems.
• Compact SOT-23-5 package supports high-density PCB layout and small analog current-sensing circuits.
• Wide operating temperature range supports industrial, power-control, and embedded-system applications.
• High common-mode rejection supports accurate high-side current measurement on active supply rails.
• Suitable for battery chargers, portable devices, power supplies, current sources, and system power monitoring.

Applications

Equivalent & Alternatives

When evaluating an INA139NA/3K equivalent, engineers should compare supply voltage range, common-mode voltage range, output type, gain-setting method, package footprint, bandwidth, offset performance, quiescent current, and system-level measurement accuracy.

Compared with INA169, INA139NA/3K is more suitable for systems that do not require current sensing above 40V. INA139NA/3K vs INA180 selection depends on whether the design needs a current-output architecture with external gain setting or a fixed-gain voltage-output current-sense amplifier. For replacement or redesign work, engineers should verify package footprint, pinout, output scaling, sense-resistor value, and ADC input range before approving an equivalent part.

Quality

INA139NA/3K should be sourced as original Texas Instruments components through traceable and controlled supply channels. Quality verification procedures may include package inspection, marking validation, reel label inspection, solderability testing, electrical parameter checking, current-sense function verification, and lot traceability review according to embedded production requirements.

Because the device is used in current measurement and power-management circuits, correct shunt-resistor selection, Kelvin sense routing, stable supply decoupling, proper load-resistor tolerance control, and calibrated ADC scaling help maintain measurement accuracy. For production systems, validation across load current, temperature, supply voltage, and common-mode voltage conditions helps reduce current-monitoring error and field failure risk.

Availability

INA139NA/3K available at Aetrix Electronics and is suitable for long lifecycle industrial and embedded sensor measurement platforms requiring stable component supply and repeatable production support.

Supply support may include volume procurement planning, scheduled delivery arrangements, traceable sourcing management, and long-term supply support for OEM, industrial equipment manufacturers, power-management system suppliers, battery-device manufacturers, and embedded control production programs.

For production builds, confirming package type, reel quantity, operating voltage range, current-sense accuracy requirements, shunt-resistor design, output scaling, lead time, and sourcing continuity helps improve procurement stability and reduce manufacturing interruption risk.

Manufacturer

Texas Instruments is a global semiconductor manufacturer providing analog ICs, embedded processors, power-management devices, amplifiers, data converters, sensors, interface products, and signal-chain components for industrial, automotive, communication, consumer, and computing applications.

For current-sensing and power-monitoring systems, Texas Instruments offers current-sense amplifiers, current shunt monitors, power monitors, instrumentation amplifiers, and precision analog devices used in battery systems, power supplies, motor drives, industrial automation, and embedded control platforms.

FAQ

What is INA139NA/3K used for?

INA139NA/3K is used for high-side current shunt measurement in battery chargers, power-management circuits, portable electronics, industrial control systems, embedded boards, and current-monitoring applications.

Where can I find the INA139NA/3K datasheet download?

The INA139NA/3K datasheet download is available from Texas Instruments. The datasheet includes electrical characteristics, pin configuration, application circuits, gain-setting guidance, package information, and layout recommendations.

What should be considered in INA139NA/3K pinout design?

INA139NA/3K pinout design should prioritize Kelvin routing from the shunt resistor, stable supply decoupling near the V+ pin, short analog signal paths, correct OUT load-resistor placement, and low-noise grounding for accurate current measurement.

Does INA139NA/3K provide voltage output directly?

INA139NA/3K provides a current output. The output current is converted into a voltage by an external load resistor, which allows designers to set the voltage gain according to the required measurement range.

What are common INA139NA/3K equivalent solutions?

Common INA139NA/3K equivalent or alternative solutions include INA169, INA138, and INA180 depending on voltage range, output type, gain architecture, package requirements, and current-sensing accuracy targets.