INA139NA/3K Texas Instruments High-Side Current Sense Amplifier IC 440kHz Variable Gain SOT-23-5 Package

INA139NA/3K Product Overview

The INA139NA/3K is a high-side, unipolar current shunt monitor from Texas Instruments, part of the INA139 series. Housed in a SOT-23-5 package, it is a high-speed, low-quiescent-current current sense amplifier. The INA139NA/3K converts a differential input voltage to a current output, and an external load resistor sets the gain from 1 to over 100. Its input common-mode and power-supply voltages are independent and range from 2.7V to 40V. The INA139NA/3K is specified for the –40°C to +125°C temperature range. With features including high CMRR (115dB) , ultra-low input bias current (10nA) , and low quiescent current (60μA), it is widely used in power management, battery chargers, portable devices, automotive electronics, and precision current sources.

INA139NA/3K Key Features

High-Side Current Sensing: INA139NA/3K supports complete unipolar high-side current measurement without disrupting the ground path.

Wide Supply & Common-Mode Range: INA139NA/3K supports 2.7V to 40V, with independent supply and common-mode voltages.

High CMRR: 115dB common-mode rejection ratio for excellent noise immunity.

Low Quiescent Current: Only 60µA typical, ideal for battery-powered devices.

Single Resistor Gain Set: External load resistor sets gain from 1 to over 100.

440kHz Bandwidth: 440kHz gain bandwidth product for high-speed current sensing.

High Precision: Input offset voltage 200µV, input bias current 10nA.

Low Offset Drift: Input offset voltage drift only 1µV/℃.

Wide Temperature Range: -40℃ to +125℃ for demanding industrial environments.

INA139NA/3K Applications

The INA139NA/3K current sense amplifier is widely used in:

INA139NA/3K Power Management & Battery Chargers: Real-time battery charge/discharge current monitoring

INA139NA/3K Portable & Backup Battery Systems: Battery current monitoring in mobile phones, laptops, etc.

INA139NA/3K Automotive Electronics: Current monitoring in vehicle power systems, motor drives, body electronics

INA139NA/3K Precision Current Sources: Current feedback element in lab instruments and industrial controls

INA139NA/3K Shunt Measurements: Power current monitoring in telephones, computers, etc.

INA139NA/3K Overcurrent Protection: Overcurrent detection with comparators

INA139NA/3K  Key Advantages

High-Side Sensing Simplifies System Design: Measures load current directly on the positive supply rail without breaking the ground path.

Wide Common-Mode Voltage Range: 2.7V to 40V, compatible with 3.3V, 5V, 12V, 24V systems.

Independent Supply & Common-Mode Voltages: Design flexibility allows connecting the supply to either side of the shunt.

Variable Gain Design: Single external resistor sets gain from 1 to over 100.

Low Power Consumption: 60µA typical quiescent current for battery-powered devices.

High Precision: 200µV offset voltage, 10nA bias current, and 115dB CMRR ensure accurate current measurement.

440kHz Bandwidth: Fast response for dynamic load monitoring.

Industrial Temperature Range: -40℃ to +125℃ for harsh industrial and automotive environments.

Compact Package: 5-pin SOT-23 saves PCB space.

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FAQ

1 What is the INA139NA/3K chip
The INA139NA/3K is a high side voltage output current shunt monitor produced by Texas Instruments (TI) commonly used to accurately measure the current flowing through a load and convert it into a voltage signal.

2 What is the core function of this INA139NA/3K
The core function of the INA139NA/3K is high side current sensing, which allows it to amplify small differential voltages across a sense resistor even when the common mode voltage is much higher than the ICs own supply voltage, achieving high precision current monitoring.

3 What are the common mode input voltage and supply voltage ranges
The INA139NA/3K's common mode input voltage range is extremely wide and can reach up to 40 volts. Its supply voltage range is 2 point 7 volts to 40 volts, which can be the same as the common mode input or significantly lower.

4 How is the gain set for this INA139NA/3K
The gain of the INA139NA/3K is not fixed but is flexibly set by the ratio of external gain setting resistors to the output load resistor, allowing the gain to be adjusted according to application requirements.

5 What are INA139NA/3K key performance parameters
The INA139NA/3K offers exceptionally high precision and bandwidth. The typical bandwidth reaches 800 kilohertz with an input offset voltage as low as plus or minus 1 millivolt and a quiescent current of only about 60 microamps, making the INA139NA/3K ideal for high precision high frequency sensing.

6 What application scenarios is this INA139NA/3K suitable for
The INA139NA/3K is widely used in current control for motor drives, overcurrent protection in switching power supplies, charge and discharge monitoring in battery management systems, and real time current feedback in industrial control systems.

7 Why is INA139NA/3K suitable for high side current sensing
The INA139NA/3K's unique design allows the input common mode voltage to operate independently of the supply voltage, enabling direct connection to the positive terminal of the power source without needing costly discrete component circuits.

8 What package and mounting method does INA139NA/3K use
The INA139NA/3K uses a compact SOT 23 5 pin surface mount package which is extremely space efficient and suitable for PCB soldering in space constrained designs to minimize the system footprint.

9 What external design considerations should be noted
For the INA139NA/3K, a small value microamp level current sense resistor must be placed in series with the input and two external resistors must be connected to the output to set the gain. Additionally, a decoupling capacitor is recommended near the supply pin.

10 What are the temperature range and environmental adaptability
The INA139NA/3K operates from minus 40 degrees Celsius to plus 125 degrees Celsius industrial grade, ensuring excellent long term stability and adaptability to harsh industrial environments.