component

INA181

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by Ray

TI current-sense amplifier, SOT-23-6. -0.2 to 26 V common mode, bidirectional with REF, 350 kHz. Datasheet-verified.

componentamplifiercurrent-sensecurrent-shunt-monitorsot-23-6texas-instruments
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Contents

README

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INA181

Texas Instruments · Current-sense amplifier · SOT-23-6

Amplifies the small voltage across a shunt resistor into a ground-referenced output a plain ADC can read. The inputs sense a common-mode bus from -0.2 V to 26 V independent of the supply, so it works high-side or low-side, and a REF pin sets the zero-current output for bidirectional current. The fixed-gain part comes in 20, 50, 100, and 200 V/V options (A1-A4). Runs from a single 2.7 to 5.5 V rail. The single-channel workhorse for board-level current measurement.

Pinout

Pin Name Type Function
1 OUT output Analog output voltage. V_OUT = Gain x (V_IN+ - V_IN-) + V_REF. Rail-to-rail output.
2 GND power_in Device ground reference.
3 IN+ input Current-sense amplifier positive input. For high-side sensing, connect to the bus-voltage side of the sense resistor; for low-side sensing, connect to the load side. Common-mode range -0.2 V to +26 V.
4 IN- input Current-sense amplifier negative input. For high-side sensing, connect to the load side of the sense resistor; for low-side sensing, connect to the ground side. Common-mode range -0.2 V to +26 V.
5 REF input Reference input that sets the output voltage for zero differential input. Tie to GND for unidirectional sensing or to a mid-supply reference for bidirectional sensing. Valid range 0 V to VS.
6 VS power_in Positive supply. Operating range 2.7 V to 5.5 V. Quiescent current 260 uA (max, INA181). Bypass with 0.1 uF ceramic to GND close to the pin.

Key specifications

Parameter Value
Type Current-sense amplifier (voltage output)
Common-mode range -0.2 V to 26 V
Gain options 20 / 50 / 100 / 200 V/V (A1-A4)
Bandwidth 350 kHz (gain 20)
Direction Bidirectional (via REF)
Supply 2.7-5.5 V
Package SOT-23-6

Ordering variants

Same part, different packaging or reel option.

  • INA181A1IDBVR (gain 20)
  • INA181A2IDBVR (gain 50)
  • INA181A3IDBVR (gain 100)
  • INA181A4IDBVR (gain 200)

CAD (KiCad official)

  • Symbol: Amplifier_Current:INA181 (KiCad official)
  • Footprint: Package_TO_SOT_SMD:SOT-23-6
  • 3D model: SOT-23-6 (KiCad packages3D, STEP)

Provenance

Data extracted from the manufacturer datasheet, not a distributor listing:

  • Datasheet: Texas Instruments datasheet (62 pp, sha256 b8e948e4b605ffaa, retrieved 2026-08-17, tier: manufacturer)
  • Extractor: ds2sf (Claude). Every pin and dimension is cited to a datasheet page; it refuses to fabricate.
  • CAD: KiCad official libraries (CC-BY-SA 4.0).

Datasheet PDF