Key Selection Information
| Selection Parameter | Confirmed Information |
|---|---|
| Measurement | Unipolar high-side current sensing |
| Supply / Common Mode | 2.7 V to 40 V recommended |
| Quiescent Current | 60 µA typical |
| Output Architecture | Current output; external RL sets voltage gain |
| Transfer Core | 1 kΩ internal transconductance network |
| Bandwidth | Up to about 440 kHz depending on output load |
| Temperature | −40°C to +125°C |
| Exact Package / Packing | SOT-23 (DBV), 5 pins; 3000-piece large tape and reel |
Product Overview
INA139NA/3K is a variable-gain high-side current-shunt monitor for buses up to 40 V. It converts shunt voltage into output current and uses an external load resistor to create the voltage presented to the ADC or control loop.
Compared with INA138, INA139 uses a different internal transconductance scaling and draws more quiescent current, while extending the recommended common-mode range to 40 V. The 1 kΩ transfer core means the same sense voltage produces more output current than the 5 kΩ INA138 architecture, so RL values should not be copied directly between the families.
The /3K suffix is the 3000-piece large tape-and-reel SOT-23-5 orderable option, not an electrical-performance grade.
For related devices, see HKEQGOO’s Current Sense Amplifiers category.
Technical Specifications
| Parameter | Verified Information |
|---|---|
| Manufacturer | Texas Instruments |
| Exact MPN | INA139NA/3K |
| Measurement | Unipolar high-side current sensing |
| Supply / Common Mode | 2.7 V to 40 V recommended |
| Quiescent Current | 60 µA typical |
| Output Architecture | Current output; external RL sets voltage gain |
| Transfer Core | 1 kΩ internal transconductance network |
| Bandwidth | Up to about 440 kHz depending on output load |
| Temperature | −40°C to +125°C |
| Exact Package / Packing | SOT-23 (DBV), 5 pins; 3000-piece large tape and reel |
| Manufacturer Status | Active / Production |
| Part Marking | E39 |
Functional Highlights
Do not reuse INA138 gain-resistor calculations
INA139 uses a 1 kΩ transconductance relationship, so its RL calculation differs from the INA138/INA168 5 kΩ family. A resistor value carried over from the wrong family can over-range the ADC or force output saturation.
Supply and bus voltage are independent
The monitor supply does not have to be the same rail as the measured high-side bus, provided both stay inside the specified operating ranges.
Design Considerations
- Calculate RL from the INA139 transfer relationship, not from an INA138 design.
- Check bandwidth and output compliance after selecting RL.
- Route the shunt sense pins as Kelvin connections and keep load-current copper out of the measurement path.
Product Status and Exact Order Code
Manufacturer status: Active / Production
Texas Instruments lists INA139NA/3K as Active / Production; SOT-23 (DBV), 5 pins; 3000-piece large tape and reel; Level-2-260C-1 YEAR; −40°C to +125°C; marking E39.
Related Engineering Resources
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