INA139NA/3K, High‑Side Current‑Sense Amplifier (Current Shunt Monitor) from TI (Texas Instruments)

Key Parameters

Common‑Mode Input Voltage: 2.7 V ~ 36 V (measured bus voltage, can be higher than the chip supply voltage)

Chip Supply Voltage (Vs): 2.7 V‑40 V

Bandwidth: Typical 220 kHz, maximum 440 kHz

Quiescent Current Iq: Typical 60 μA, maximum 125 μA

Offset Voltage: Max ±1000 μV

CMRR (Common‑Mode Rejection Ratio): Minimum 100 dB

Gain Configuration: Programmable gain from 1 to 100 via external single resistor RL

Output Type: Current output; convert to voltage signal by external resistor

Operating Temperature: ‑40 ℃ ~ +125 ℃

Package: SOT‑23‑5 (DBV)

Packaging: T&R Tape‑and‑Reel, 3000 pcs per reel

Main Features

High‑Side Current Sensing: Samples the voltage drop across shunt resistor Rs on the positive power rail (high‑side). No need to break the GND loop and no interference to load ground, which is its core advantage.

Independent Supply and Common‑Mode Voltage: The chip supply can differ from the measured bus voltage. It can measure current on a 36 V bus while the chip is powered by 5 V.

Single‑resistor Gain Setting: Output gain is configured with only one external load resistor RL, delivering simple circuitry and reduced BOM count.

Current‑output Architecture: Output current is proportional to the voltage across the shunt resistor. Good noise immunity and suitable for long‑distance transmission.

Unipolar Measurement: Only unidirectional current measurement supported; bidirectional current sensing is not available.

Peer‑series Reference: INA169, common‑mode voltage increased to 60 V with identical other circuit logic.

Applications

Power & Battery Management

‑ Battery charge‑discharge current monitoring, backup power systems

‑ Current monitoring for DC‑DC power modules and power adapters

‑ Overcurrent monitoring for server and industrial power supplies

Industrial Equipment

‑ Auxiliary current sampling for PLCs, industrial controllers and servos

‑ Motor‑drive overcurrent protection and short‑circuit detection

‑ Supply‑current acquisition for portable industrial instruments

Consumer Electronics

‑ Current monitoring for laptop and desktop mainboards

‑ Current detection for chargers and power banks

Tips

Only unidirectional current can be measured. Select INA219, INA226, etc. for bidirectional sensing.

High‑side sampling is ideal for systems where the negative ground cannot be disconnected. Compact SOT‑23‑5 package fits space‑constrained PCBs.

The output is current; an external resistor is required for the rear‑end MCU to convert it into voltage before feeding into the ADC.