INA381A1
Current Sense Amplifier with Integrated ComparatorThe INA381A1 is a current sense amplifier with integrated comparator from Texas Instruments. View the full INA381A1 datasheet below including key specifications, electrical characteristics, absolute maximum ratings.
INA381A1 shares its datasheet with INA381A3, whose page lists every part number it covers.
Official INA381A1 datasheet (PDF) — the source this page was extracted from.
INA381A1 Key Specifications
| Parameter | Value |
|---|---|
| Accuracy | ±1% |
| Function | Current Sense |
| Mounting Type | Surface Mount |
| Operating Temperature | -40°C ~ 125°C (TA) |
| Package / Case | 8-WFDFN Exposed Pad |
| Packaging | MouseReel |
| Sensing Method | High/Low-Side |
| Standard Pack Qty | 3000 |
| Supplier Device Package | 8-WSON (2x2) |
| Input Voltage Range | 0V ~ 26V |
INA381A1 Overview
Part: INA381 — Texas Instruments
Type: High-Speed, Current Sense Amplifier With Integrated Comparator
Description: The INA381 is a 26-V common-mode current-sensing amplifier with an integrated high-speed comparator, capable of detecting overcurrent conditions by measuring voltage across a shunt resistor and comparing it to a user-defined threshold.
Operating Conditions:
- Supply voltage: 2.7 V to 5.5 V
- Operating temperature: -40 to +125 °C
- Common-mode input voltage: -0.2 V to 26 V
Absolute Maximum Ratings:
- Max supply voltage: 6 V
- Max junction temperature: 150 °C
- Max storage temperature: 150 °C
Key Specs:
- Common-mode input range: -0.2 V to +26 V
- Offset voltage (VCM = 12 V, TA = 25°C): ±500 μV (maximum)
- Offset voltage (VCM = 0 V, TA = 25°C): ±150 μV (maximum)
- Offset voltage drift: 1 μV/°C (maximum)
- Gain error (TA = 25°C): ±1% (maximum)
- Gain error drift: 20 ppm/°C (maximum)
- Quiescent current (VSENSE = 10 mV, TA = +25°C): 250 μA (typical), 350 μA (maximum)
- Comparator propagation delay (CMPIN overdrive = 20 mV): 0.4 μs (typical), 1 μs (maximum)
- Comparator hysteresis: 50 mV
Features:
- High accuracy amplifier with low offset voltage and drift
- Available amplifier gains: 20 V/V, 50 V/V, 100 V/V, 200 V/V
- Open-drain comparator with 50 mV hysteresis
- Alert threshold set through external reference voltage
- Supports transparent and latching comparator modes
- Fast alert response time
Applications:
- Merchant network and server PSU
- Merchant DC/DC
- DC-input BLDC motor drive
- Cordless power tool
- Headsets, headphones and earbuds
Package:
- VSSOP (10) - 3.00 mm × 3.00 mm
- WSON (8) - 2.00 mm × 2.00 mm
INA381A1 Features
-
1 · 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:
-
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
-
INA381A1: 20 V/V
-
INA381A2: 50 V/V
-
INA381A3: 100 V/V
-
INA381A4: 200 V/V
INA381A1 Applications
- Merchant network and server PSU
- Merchant DC/DC
- DC-input BLDC motor drive
- Cordless power tool
- Headsets, headphones and earbuds
INA381A1 Pin Configuration
INA381A1 Electrical Characteristics
at TA = 25°C, VSENSE = VIN+ - VIN= 10 mV, VS = 5 V, VIN+ = 12 V, and CMPREF = 2 V (unless otherwise noted)
| PARAMETER | TEST CONDITIONS | MIN | TYP | MAX | UNIT | |
|---|---|---|---|---|---|---|
| INPUT | ||||||
| CMRR | Common-mode rejection ratio, RTI (1) | V IN+ = 0 V to 26 V, T A = -40°C to +125°C | 84 | 100 | dB | |
| V | Offset voltage, RTI (1) | V IN+ = 12 V, V IN- = 12 V | ±100 | ±500 | ||
| OS | V IN+ = 0 V, V IN- = 0 V | ±25 | ±150 | μ V | ||
| dV OS /dT | Offset voltage drift, RTI (1) | T A = -40°C to +125°C | 0.1 | 1 | μ V/°C | |
| PSRR | Power-supply rejection ratio | V S = 2.7 V to 5.5 V, T A = -40°C to +125°C | ±8 | ±40 | μ V/V | |
| I B | Input bias current | V SENSE = 0 mV, I B+ , I B- | 80 | μ A | ||
| I OS | Input offset current | V SENSE = 0 mV | ±0.05 | μ A | ||
| OUTPUT | Gain | INA381A1 | 20 | |||
| G | INA381A2 | 50 | ||||
| G | INA381A3 | 100 | V/V | |||
| G | INA381A4 | 200 | ||||
| E G | Gain error | VOUT = 0.5 V to V S - 0.5 V | ±0.1% | ±1% | ||
| Gain error drift Nonlinearity error | T A = -40°C to +125°C V OUT = 0.5 V to V S - 0.5 V | 1.5 ±0.01% | 20 | ppm/°C | ||
| Maximum capacitive load | No sustained oscillation | 1 | nF | |||
| VOLTAGE | OUTPUT | |||||
| Swing to V S power-supply rail | R L = 10 k Ω to GND, T A = -40°C to +125°C | V S - 0.02 | V S - 0.05 | V | ||
| Swing to GND (2) | R L = 10 k Ω to GND, T A = -40°C to +125°C | V GND + 0.0005 | V GND + 0.005 | V | ||
| FREQUENCY RESPONSE | FREQUENCY RESPONSE | |||||
| BW | Bandwidth | INA381A1 INA381A2 INA381A3 INA381A4 | 350 210 150 105 | kHz kHz kHz kHz | ||
| SR | Slew rate | 2 | V/μs | |||
| NOISE | Voltage noise density | 40 | nV/ √ Hz | |||
| COMPARATOR | ||||||
| t p | Propagation delay time, comparator only | CMPIN Input overdrive = 20 mV | 0.4 | 1 | μs | |
| Large-signal propagation delay, comparator only | CMPIN step = 0.5 V to 4.5, V CMPREF = 4 V | 0.4 | 2 | μs | ||
| Small-signal total alert propogation delay, comparator and amplifier | Input overdrive = 1 mV | 2 | 5 | μs | ||
| Slew rate limited total alert propagation delay, comparator and amplifier | V OUT = 0.5 V to 4.5, V CMPREF = 4 V | 3 | 10 | μs | ||
| V OS | Comparator offset voltage | ±1 | ±5 | mV | ||
| HYS | Hysteresis | 50 | mV | |||
| V IH | High-level input voltage | 1.4 | 6 | V | ||
| V IL | Low-level input voltage | 0 | 0.4 | V | ||
| V OL | Alert low-level output voltage | I OL = 3 mA | 70 | 300 | mV | |
| ALERT pin leakage input current | V OH = 3.3 V | 0.1 | 1 | μ A | ||
| Digital leakage input current | 0 ≤ V IN ≤ V S | 1 | μ A | |||
| POWER | SUPPLY | |||||
| V SENSE = 10 mV, T A = +25°C | 250 | 350 | μ A | |||
| I Q | Quiescent current | T A = -40°C to +125°C | 450 |
INA381A1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted) (1)
| MIN | MAX | UNIT | |||
|---|---|---|---|---|---|
| V S | Supply voltage | Supply voltage | 6 | V | |
| V IN+ ,V IN- | Analog inputs (IN+, IN-) | Differential (V IN+ ) - (V IN- ) (2) | -26 | 26 | V |
| V IN+ ,V IN- | Analog inputs (IN+, IN-) | Common-mode (3) | GND - 0.3 | 26 | V |
| V I | Analog input | CMPIN | GND - 0.3 | (V S ) + 0.3 | V |
| V I | Analog input | CMPREF | GND - 0.3 | (V S ) + 0.3 | V |
| V O | Analog output | OUT | GND - 0.3 | (V S ) + 0.3 | V |
| Digital input | RESET | GND - 0.3 | (V S ) + 0.3 | V | |
| Digital output | ALERT | GND - 0.3 | 6 | V | |
| T J | Junction temperature | Junction temperature | 150 | °C | |
| T stg | Storage temperature | Storage temperature | -65 | 150 | °C |
INA381A1 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted)
| MIN | NOM | MAX | UNIT | ||
|---|---|---|---|---|---|
| V CM | Common-mode input voltage | -0.2 | 12 | 26 | V |
| V S | Operating supply voltage | 2.7 | 5 | 5.5 | V |
| T A | Operating free-air temperature | -40 | 125 | °C |
INA381A1 Thermal Information
| INA381 | INA381 | ||
|---|---|---|---|
| THERMAL METRIC (1) | THERMAL METRIC (1) | DGS (VSSOP) | DSG (WSON) |
| 10 PINS | 8 PINS | ||
| R θ JA | Junction-to-ambient thermal resistance | 188.6 | 77 |
| R θ JC(top) | Junction-to-case (top) thermal resistance | 78.1 | 96.5 |
| R θ JB | Junction-to-board thermal resistance | 111.0 | 43.4 |
| Ψ JT | Junction-to-top characterization parameter | 17.5 | 5.4 |
| Ψ JB | Junction-to-board characterization parameter | 109.2 | 43.6 |
| R θ JC(bot) | Junction-to-case (bottom) thermal resistance | N/A | 18.8 |
INA381A1 Typical Application
Variants on the same datasheet
These parts have exact links to the same datasheet. They are candidates to compare, not verified drop-in replacements; check package, pinout and electrical limits.
| Part Number | Manufacturer | Package |
|---|---|---|
| INA381 | Texas Instruments | — |
| INA381A2 | Texas Instruments | WSON-8 |
| INA381A3 | Texas Instruments | WSON-8 |
| INA381A3IDGSR | Texas Instruments | VSSOP-10 |
| INA381A3IDGSR.B | Texas Instruments | VSSOP-10 |
| INA381A3IDGST | Texas Instruments | VSSOP-10 |
| INA381A3IDSGR | Texas Instruments | 8-WFDFN Exposed Pad |
| INA381A3IDSGR.B | Texas Instruments | WSON-8 2x2mm |
| INA381A3IDSGT | Texas Instruments | VSSOP-10 |
| INA381A4 | Texas Instruments | WSON-8 |
Other Current Sensors
- INA381A3IDSGR – Texas Instruments, Current Sense Amplifier with Integrated Comparator
- INA219 – Texas Instruments, Current/Power Monitor
- ACS712ELC-05A – Allegro MicroSystems, Hall Current Sensor Module
- ACS712ELC-10A – Allegro MicroSystems, Hall Current Sensor Module
- ACS712ELC-30A – Allegro MicroSystems, Hall Current Sensor Module
- ACS72981ELR – Allegro MicroSystems, Hall-Effect Current Sensor IC
- ACS72981KLR – Allegro MicroSystems, Hall-Effect Linear Current Sensor
- ACS72981LLR – Allegro MicroSystems, Hall-Effect Linear Current Sensor IC
All Current Sensors datasheetsAll Texas Instruments datasheets (2,418)
Ask your AI agent about the INA381A1
Connect SheetsData to Claude, Cursor, Codex or any MCP client and your agent reads this datasheet for you: pinout, limits, register maps and design checks, with the numbers taken from the PDF.
claude mcp add --transport http sheetsdata https://mcp.sheetsdata.com/mcp
Then ask: "Can the INA381A1 run from my 12 V rail? Check it against the datasheet limits."
Create a free account $2 of usage every month, no card needed.