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INA381

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26-V, 350-kHz current sense amplifier with integrated over-current comparator

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Data sheet

INA381

ACTIVE
Data sheet Order now

Product details

Product type Analog output with integrated comparator Common-mode voltage (max) (V) 26 Common-mode voltage (min) (V) -0.2 Input offset (±) (max) (µV) 150 Input offset drift (±) (typ) (µV/°C) 0.1 Features Alert Function, Low-side Capable Rating Catalog Voltage gain (V/V) 20, 50, 100, 200 CMRR (min) (dB) 84 Bandwidth (kHz) 105, 150, 210, 350 Iq (max) (mA) 0.45 Number of channels 1 Comparators (#) 1 Gain error (%) 1 Gain error drift (±) (max) (ppm/°C) 20 Slew rate (V/µs) 2 Operating temperature range (°C) -40 to 125
Product type Analog output with integrated comparator Common-mode voltage (max) (V) 26 Common-mode voltage (min) (V) -0.2 Input offset (±) (max) (µV) 150 Input offset drift (±) (typ) (µV/°C) 0.1 Features Alert Function, Low-side Capable Rating Catalog Voltage gain (V/V) 20, 50, 100, 200 CMRR (min) (dB) 84 Bandwidth (kHz) 105, 150, 210, 350 Iq (max) (mA) 0.45 Number of channels 1 Comparators (#) 1 Gain error (%) 1 Gain error drift (±) (max) (ppm/°C) 20 Slew rate (V/µs) 2 Operating temperature range (°C) -40 to 125
VSSOP (DGS) 10 14.7 mm² (3 mm × 4.9 mm) WSON (DSG) 8 4 mm² (2 mm × 2 mm)
  • Common-mode input range: –0.2 V to +26 V
  • High accuracy amplifier:
    • Offset voltage at TA = 25°C
      • 500 µV (maximum) at VCM = 12 V
      • 150 µV (maximum) at VCM = 0 V
    • Offset voltage drift: 1 µV/°C (maximum)
    • Gain error: 1% (maximum) at 25°C
    • Gain error drift: 20 ppm/°C (maximum)
  • Available amplifier gains:
    • INA381A1: 20 V/V
    • INA381A2: 50 V/V
    • INA381A3: 100 V/V
    • INA381A4: 200 V/V
  • Open-drain comparator:
    • Hysteresis: 50 mV
    • Propagation delay: 400 ns (typ)
    • Alert threshold set through external reference voltage
    • Supports transparent and latching modes
  • Packages: VSSOP-10 and WSON-8
  • Common-mode input range: –0.2 V to +26 V
  • High accuracy amplifier:
    • Offset voltage at TA = 25°C
      • 500 µV (maximum) at VCM = 12 V
      • 150 µV (maximum) at VCM = 0 V
    • Offset voltage drift: 1 µV/°C (maximum)
    • Gain error: 1% (maximum) at 25°C
    • Gain error drift: 20 ppm/°C (maximum)
  • Available amplifier gains:
    • INA381A1: 20 V/V
    • INA381A2: 50 V/V
    • INA381A3: 100 V/V
    • INA381A4: 200 V/V
  • Open-drain comparator:
    • Hysteresis: 50 mV
    • Propagation delay: 400 ns (typ)
    • Alert threshold set through external reference voltage
    • Supports transparent and latching modes
  • Packages: VSSOP-10 and WSON-8

The INA381 includes both a 26-V common-mode, current-sensing amplifier and a high-speed comparator. This device detects overcurrent conditions by measuring the voltage developed across a current-shunt resistor and comparing that voltage to a user-defined threshold limit set by the comparator reference pin. The current-shunt monitor can measure differential voltage signals on common-mode voltages that vary from –0.2 V up to 26 V, independent of the supply voltage.

The open-drain alert output can be configured to operate in two modes: transparent or latched. In transparent mode, the output status follows the input state. In latched mode, the alert output is cleared only when the latch is reset. The standalone comparator large-signal alert response time is less than 2 µs, allowing for quick detection of overcurrent events. The total system overcurrent protection response time provided by the INA381 is less than 10 µs.

This device operates from a single 2.7-V to 5.5-V supply, drawing a maximum supply current of 350 µA. The device is specified over an operating temperature range of –40°C to +125°C, and is available in 8-pin WSON and 10-pin VSSOP packages.

 

 

The INA381 includes both a 26-V common-mode, current-sensing amplifier and a high-speed comparator. This device detects overcurrent conditions by measuring the voltage developed across a current-shunt resistor and comparing that voltage to a user-defined threshold limit set by the comparator reference pin. The current-shunt monitor can measure differential voltage signals on common-mode voltages that vary from –0.2 V up to 26 V, independent of the supply voltage.

The open-drain alert output can be configured to operate in two modes: transparent or latched. In transparent mode, the output status follows the input state. In latched mode, the alert output is cleared only when the latch is reset. The standalone comparator large-signal alert response time is less than 2 µs, allowing for quick detection of overcurrent events. The total system overcurrent protection response time provided by the INA381 is less than 10 µs.

This device operates from a single 2.7-V to 5.5-V supply, drawing a maximum supply current of 350 µA. The device is specified over an operating temperature range of –40°C to +125°C, and is available in 8-pin WSON and 10-pin VSSOP packages.

 

 
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Technical documentation

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Top documentation Type Title Format options Date
* Data sheet INA381 26-V, High-Speed, Current Sense Amplifier With Integrated Comparator datasheet (Rev. B) PDF | HTML Oct 10, 2019
Application note Using a PCB Copper Trace as a Current Sense Shunt Resistor (Rev. A) PDF | HTML Apr 27, 2026
Application note Risks and Prevention of ESD, EOS, and Latch Up Events for Current Sense Amplifiers PDF | HTML Nov 18, 2024
Application brief Current Sensing in Collaborative and Industrial Robotic Arms (Rev. B) PDF | HTML Jul 24, 2023
Application brief Improving Power Amplifier Efficiency With Current Monitors (Rev. B) PDF | HTML Jul 24, 2023
Application brief Current Sensing in Mobile Robots PDF | HTML Nov 29, 2022
E-book An Engineer's Guide to Current Sensing (Rev. B) Apr 12, 2022
Application brief Measuring Current To Detect Out-of-Range Conditions (Rev. D) PDF | HTML Mar 10, 2022
Application brief Measuring Current for Handle Multiple Out-of-Range Conditions (Rev. C) PDF | HTML Oct 4, 2021
Selection guide Current Sense Amplifiers (Rev. E) Sep 20, 2021
Analog design Journal Current sensing in high‐power USB Type‐C applications Dec 21, 2020
Application brief Bidirectional, Low-Side Phase Current Sensing With Onboard Overcurrent Detection (Rev. D) Mar 6, 2019
Technical article A key to accurate system thermal management: monitoring both current flow and temp PDF | HTML Oct 4, 2018
Circuit design Overcurrent event detection circuit Jul 31, 2018
Application brief Low-Drift, Low-Side Current Measurements for Three-Phase Systems (Rev. B) Sep 5, 2017

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

INA381EVM — INA381 Current Sense Amplifier With Integrated Over-Current Comparator Evaluation Module

The INA381 is a current sense monitor solution with an integrated comparator for detecting overcurrent conditions that provides ease of use and high performance for cost-sensitive applications.  The INA381EVM is intended to provide basic functional evaluation of the device family. The fixture (...)
User guide: PDF
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Simulation model

INA381 TINA-TI Reference Design

SBOMAL8.TSC (5235 KB) - TINA-TI reference design
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Simulation model

INA381 TINA-TI Spice Model

SBOMAL9.ZIP (40 KB) - TINA-TI Spice model
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Simulation model

INA381A1 PSpice Model

SBOMBD6.ZIP (29 KB) - TISpice Model
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Simulation model

INA381A2 PSpice Model

SBOMBC0.ZIP (29 KB) - PSpice model
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Simulation model

INA381A3 PSpice Model

SBOMBF6.ZIP (28 KB) - PSpice model
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Simulation model

INA381A4 PSpice Model

SBOMBF3.ZIP (28 KB) - PSpice model
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Simulation tool

SBOC519 — Low-Side OCP Source Files for SBOA297

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Simulation tool

SBOC520 — High-Side OCP Source Files for SBOA297

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Simulation tool

TINA-TI — SPICE-based analog simulation program

TINA-TI provides all the conventional DC, transient and frequency domain analysis of SPICE and much more. TINA has extensive post-processing capability that allows you to format results the way you want them. Virtual instruments allow you to select input waveforms and probe circuit nodes voltages (...)

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Calculation tool

ANALOG-ENGINEER-CALC — PC software analog engineer's calculator

The analog engineer’s calculator is designed to speed up many of the repetitive calculations that analog circuit design engineers use on a regular basis. This PC-based tool provides a graphical interface with a list of various common calculations ranging from setting operational-amplifier (...)

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Calculation tool

CS-AMPLIFIER-ERROR-TOOL — Current Sense Amplifier Comparison and Error Tool

This Excel calculator provides a comparison between two and five of our standard current sense amplifiers, delivering a chart containing the basic parameters of each device. This calculator also takes system condition inputs from users such as common-mode voltage, supply voltage, shunt resistor (...)
Supported products & hardware
Design tool

CIRCUIT060034 — Overcurrent event detection circuit

This is a unidirectional current sensing solution generally referred to as overcurrent protection (OCP) that can provide an overcurrent alert signal to shut off a system for a threshold current and re-engage the system once the output drops below a desired voltage (Vout_release) lower than the (...)
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Reference design

TIDA-00302 — Current Shunt Monitor with Transient Robustness Reference Design

This high-side current shunt monitor is used to measure the voltage developed across a current-sensing resistor when current passes through it.

Additionally, an external protection circuit is implemented to provide surge and fast-transient protection and demonstrate the different immunity levels to (...)

Supported products & hardware
Reference design

TIDA-010011 — High efficiency power supply architecture reference design for protection relay processor module

This reference design showcases various power architectures for generating multiple voltage rails for an application processor module, requiring >1A load current and high efficiency . The required power supply is generated using 5-, 12- or 24-V DC input from the backplane. Power supplies are (...)
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Package Pins CAD symbols, footprints & 3D models
VSSOP (DGS) 10 Ultra Librarian
WSON (DSG) 8 Ultra Librarian
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