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  • INAx181 Bidirectional, Low- and High-Side Voltage Output, Current-Sense Amplifiers

    • SBOS793H April   2017  – November 2023 INA181 , INA2181 , INA4181

      PRODUCTION DATA  

  • CONTENTS
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  • INAx181 Bidirectional, Low- and High-Side Voltage Output, Current-Sense Amplifiers
  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 High Bandwidth and Slew Rate
      2. 7.3.2 Bidirectional Current Monitoring
      3. 7.3.3 Wide Input Common-Mode Voltage Range
      4. 7.3.4 Precise Low-Side Current Sensing
      5. 7.3.5 Rail-to-Rail Output Swing
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Mode
      2. 7.4.2 Unidirectional Mode
      3. 7.4.3 Bidirectional Mode
      4. 7.4.4 Input Differential Overload
      5. 7.4.5 Shutdown Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Basic Connections
      2. 8.1.2 RSENSE and Device Gain Selection
      3. 8.1.3 Signal Filtering
      4. 8.1.4 Summing Multiple Currents
      5. 8.1.5 Detecting Leakage Currents
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
    3. 8.3 Power Supply Recommendations
      1. 8.3.1 Common-Mode Transients Greater Than 26 V
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Development Support
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information
  13. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • DCK|6
    • MPDS114F
  • DBV|6
    • MPDS026Q
Thermal pad, mechanical data (Package|Pins)
Orderable Information
  • sbos793h_oa
  • sbos793h_pm
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Data Sheet

INAx181 Bidirectional, Low- and High-Side Voltage Output,
Current-Sense Amplifiers

1 Features

  • Common-mode range (VCM): –0.2 V to +26 V
  • High bandwidth: 350 kHz (A1 devices)
  • Offset voltage:
    • ±150 µV (maximum) at VCM = 0 V
    • ±500 µV (maximum) at VCM = 12 V
  • Output slew rate: 2 V/µs
  • Bidirectional current-sensing capability
  • Accuracy:
    • ±1% gain error (maximum)
    • 1-µV/°C offset drift (maximum)
  • Gain options:
    • 20 V/V (A1 devices)
    • 50 V/V (A2 devices)
    • 100 V/V (A3 devices)
    • 200 V/V (A4 devices)
  • Quiescent current: 260 µA maximum (INA181)

2 Applications

  • Motor control
  • Battery monitors and balancers
  • Power management
  • Lighting control
  • Solar inverters
GUID-48D266A9-40ED-4ADB-95F0-4AEEE0718FDF-low.gif Typical Application Circuit

3 Description

The INA181, INA2181, and INA4181 (INAx181) current sense amplifiers are designed for cost-optimized applications. These devices are part of a family of bidirectional, current-sense amplifiers (also called current-shunt monitors) that sense voltage drops across current-sense resistors at common-mode voltages from –0.2 V to +26 V, independent of the supply voltage. The INAx181 family integrates a matched resistor gain network in four, fixed-gain device options: 20 V/V, 50 V/V, 100 V/V, or 200 V/V. This matched gain resistor network minimizes gain error and reduces the temperature drift.

These devices operate from a single 2.7-V to 5.5-V power supply. The single-channel INA181 draws a maximum supply current of 260 µA; whereas, the dual-channel INA2181 draws a maximum supply current of 500 µA, and the quad-channel INA4181 draws a maximum supply current of 900 µA.

The INA181 is available in both the 6-pin, SOT-23 and SC70 packages. The INA2181 is available in 10-pin, VSSOP and WSON packages. The INA4181 is available in a 20-pin, TSSOP package. All device options are specified over the extended operating temperature range of –40°C to +125°C.

Package Information
PART NUMBER PACKAGE(1) PACKAGE SIZE(2)
INA181 DBV (SOT-23, 6) 2.90 mm × 2.80 mm
DCK (SC70, 6) 2.00 mm × 2.10 mm
INA2181 DGS (VSSOP, 10) 3.00 mm × 4.90 mm
DSQ (WSON, 10) 2.00 mm × 2.00 mm
INA4181 PW (TSSOP, 20) 6.50 mm × 6.40 mm
(1) For all available packages, see Section 11.
(2) The package size (length × width) is a nominal value and includes pins, where applicable.

4 Device Comparison

Table 4-1 Device Comparison
PRODUCT NUMBER OF CHANNELS GAIN (V/V)
INA181A1 1 20
INA181A2 1 50
INA181A3 1 100
INA181A4 1 200
INA2181A1 2 20
INA2181A2 2 50
INA2181A3 2 100
INA2181A4 2 200
INA4181A1 4 20
INA4181A2 4 50
INA4181A3 4 100
INA4181A4 4 200

5 Pin Configuration and Functions

GUID-BBFE994F-8E9E-4CBC-92FA-505E626FE572-low.svg Figure 5-1 INA181: DBV Package6-Pin SOT-23Top View
GUID-20231113-SS0I-30JQ-5W3N-D8RCZGWXW8XS-low.svg Figure 5-2 INA181: DCK Package6-Pin SC70Top View
Table 5-1 Pin Functions: INA181 (Single Channel)
PIN TYPE DESCRIPTION
NAME SOT-23 SC70
GND 2 2 Analog Ground
IN– 4 5 Analog input Current-sense amplifier negative input. For high-side applications, connect to load side of sense resistor. For low-side applications, connect to ground side of sense resistor.
IN+ 3 4 Analog input Current-sense amplifier positive input. For high-side applications, connect to bus-voltage side of sense resistor. For low-side applications, connect to load side of sense resistor.
OUT 1 6 Analog output Output voltage
REF 5 1 Analog input Reference input
VS 6 3 Analog Power supply, 2.7 V to 5.5 V
GUID-3EAC79D8-57C0-41D7-BDB2-FF442BCB3BF3-low.svgFigure 5-3 INA2181: DGS Package10-Pin VSSOPTop View
GUID-F870425D-1DE7-486A-9158-F18C3A8948CA-low.svg
A. Thermal Pad can be left floating or connected to GND.
Figure 5-4 INA2181: DSQ Package10-Pin WSONTop View
GUID-4F29C91C-B43B-4E64-B775-892247FBEAD0-low.svg Figure 5-5 INA4181: PW Package20-Pin TSSOPTop View
Table 5-2 Pin Functions: INA2181 (Dual Channel) and INA4181 (Quad Channel)
PIN TYPE DESCRIPTION
NAME INA2181 INA4181
GND 4 16 Analog Ground
IN–1 2 3 Analog input Current-sense amplifier negative input for Channel 1. For high-side applications, connect to load side of Channel 1 sense resistor. For low-side applications, connect to ground side of Channel 1 sense resistor.
IN+1 3 4 Analog input Current-sense amplifier positive input for Channel 1. For high-side applications, connect to bus-voltage side of Channel 1 sense resistor. For low-side applications, connect to load side of Channel 1 sense resistor.
IN–2 8 7 Analog input Current-sense amplifier negative input for Channel 2. For high-side applications, connect to load side of Channel 2 sense resistor. For low-side applications, connect to ground side of Channel 2 sense resistor.
IN+2 7 6 Analog input Current-sense amplifier positive input for Channel 2. For high-side applications, connect to bus-voltage side of Channel 2 sense resistor. For low-side applications, connect to load side of Channel 2 sense resistor.
IN–3 — 14 Analog input Current-sense amplifier negative input for Channel 3. For high-side applications, connect to load side of Channel 3 sense resistor. For low-side applications, connect to ground side of Channel 3 sense resistor.
IN+3 — 15 Analog input Current-sense amplifier positive input for Channel 3. For high-side applications, connect to bus-voltage side of Channel 3 sense resistor. For low-side applications, connect to load side of Channel 3 sense resistor.
IN–4 — 18 Analog input Current-sense amplifier negative input for Channel 4. For high-side applications, connect to load side of Channel 4 sense resistor. For low-side applications, connect to ground side of Channel 4 sense resistor.
IN+4 — 17 Analog input Current-sense amplifier positive input for Channel 4. For high-side applications, connect to bus-voltage side of Channel 4 sense resistor. For low-side applications, connect to load side of Channel 4 sense resistor.
NC — 10, 11 — NC denotes no internal connection. These pins can be left floating or connected to any voltage between VS and ground.
OUT1 1 2 Analog output Channel 1 output voltage
OUT2 9 8 Analog output Channel 2 output voltage
OUT3 — 13 Analog output Channel 3 output voltage
OUT4 — 19 Analog output Channel 4 output voltage
REF1 5 1 Analog input Channel 1 reference voltage, 0 to VS
REF2 6 9 Analog input Channel 2 reference voltage, 0 to VS
REF3 — 12 Analog input Channel 3 reference voltage, 0 to VS
REF4 — 20 Analog input Channel 4 reference voltage, 0 to VS
VS 10 5 Analog Power supply pin, 2.7 V to 5.5 V

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
Supply voltage, VS 6 V
Analog inputs, IN+, IN– (2) Differential (VIN+) – (VIN–) –26 26 V
Common-mode (3) GND – 0.3 26
Input voltage range at REF pin  GND – 0.3 VS + 0.3 V
Output Voltage GND – 0.3 VS + 0.3 V
Maximum output current, IOUT 8 mA
Operating fee-air temperature, TA –55 150 °C
Junction temperature, TJ 150 °C
Storage temperature, Tstg –65 150 °C
(1) Operation outside the Absolute Maximum Ratings may cause permanent device damage. Absolute Maximum Ratings do not imply functional operation of the device at these or any other conditions beyond those listed under Recommended Operating Conditions. If used outside the Recommended Operating Conditions but within the Absolute Maximum Ratings, the device may not be fully functional, and this may affect device reliability, functionality, performance, and shorten the device lifetime.
(2) VIN+ and VIN– are the voltages at the IN+ and IN– pins, respectively.
(3) Input voltage at any pin can exceed the voltage shown if the current at that pin is limited to 5 mA.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±3000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±1000
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN NOM MAX UNIT
VCM Common-mode input voltage (IN+ and IN–) –0.2 12 26 V
VS Operating supply voltage 2.7 5 5.5 V
TA Operating free-air temperature –40 125 °C

6.4 Thermal Information

THERMAL METRIC (1) INA181 INA2181 INA4181 UNIT
DCK (SC70) DBV (SOT-23) DSQ (WSON) DGS (VSSOP) PW (TSSOP)
6 PINS 6 PINS 10 PINS 10 PINS 14 PINS
RθJA Junction-to-ambient thermal resistance 188.0 198.7 74.5 177.3 97.0 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 140.8 120.9 89.7 68.7 37.7 °C/W
RθJB Junction-to-board thermal resistance 78.8 52.3 39.8 98.4 48.3 °C/W
ψJT Junction-to-top characterization parameter 62.1 30.3 3.7 12.6 3.6 °C/W
ψJB Junction-to-board characterization parameter 78.5 52.0 39.7 96.9 47.9 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance N/A N/A 16.8 N/A N/A °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report.

6.5 Electrical Characteristics

at TA = 25°C, VS = 5 V, VREF = VS / 2, VIN+ = 12 V, and VSENSE = VIN+ – VIN– (unless otherwise noted)
PARAMETER CONDITIONS MIN TYP MAX UNIT
INPUT
CMRR Common-mode rejection ratio, RTI (1) VIN+ = 0 V to 26 V, VSENSE = 0 mV,
TA = –40°C to +125°C		 84 100 dB
VOS Offset voltage, RTI VSENSE = 0 mV, VIN+ = 0 V ±25 ±150 μV
VSENSE = 0 mV ±100 ±500 μV
dVOS/dT Offset drift, RTI VSENSE = 0 mV, TA = –40°C to +125°C 0.2 1 μV/°C
PSRR RTI vs power supply ratio VS = 2.7 V to 5.5 V, VIN+ = 12 V,

VSENSE = 0 mV		 ±8 ±40 μV/V
IIB Input bias current VSENSE = 0 mV, VIN+ = 0 V -6 μA
VSENSE = 0 mV 75 μA
IIO Input offset current VSENSE = 0 mV ±0.05 μA
OUTPUT
G Gain A1 devices 20 V/V
A2 devices 50 V/V
A3 devices 100 V/V
A4 devices 200 V/V
EG Gain error VOUT = 0.5 V to VS – 0.5 V,
TA = –40°C to +125°C		 ±0.1% ±1%
Gain error vs temperature TA = –40°C to +125°C 1.5 20 ppm/°C
Nonlinearity error VOUT = 0.5 V to VS – 0.5 V ±0.01%
Maximum capacitive load No sustained oscillation 1 nF
VOLTAGE OUTPUT (2) 
VSP Swing to VS power-supply rail (3) RL = 10 kΩ to GND, TA = –40°C to +125°C (VS) – 0.02 (VS) – 0.03 V
VSN Swing to GND (3) RL = 10 kΩ to GND,  TA = –40°C to +125°C (VGND) + 0.0005 (VGND) + 0.005 V
FREQUENCY RESPONSE
BW Bandwidth A1 devices, CLOAD = 10 pF 350 kHz
A2 devices, CLOAD = 10 pF 210 kHz
A3 devices, CLOAD = 10 pF 150 kHz
A4 devices, CLOAD = 10 pF 105 kHz
SR Slew rate 2 V/μs
NOISE, RTI (1)
Voltage noise density 40 nV/√Hz
POWER SUPPLY
IQ Quiescent current INA181 VSENSE = 0 mV 195 260 μA
VSENSE = 0 mV, TA = –40°C to +125°C 300
INA2181 VSENSE = 0 mV  356 500 μA
VSENSE = 0 mV, TA = –40°C to +125°C 520
INA4181 VSENSE = 0 mV  690 900 μA
VSENSE = 0 mV, TA = –40°C to +125°C 1000
(1) RTI = referred-to-input.
(2) See Output Voltage Swing vs Output Current
(3) Swing specifications are tested with an overdriven input condition.

6.6 Typical Characteristics

at TA = 25°C, VS = 5 V, VREF = VS / 2, and VIN+ = 12 V (unless otherwise noted)

GUID-1039A418-3E29-49F1-98E5-947519FBEC3C-low.gif
Figure 6-1 Input Offset Voltage Production Distribution A1
GUID-F9AAAB81-FAB7-4EBF-969B-3613096FC261-low.gif
Figure 6-3 Input Offset Voltage Production Distribution A3
GUID-710D2C73-34BF-4BCE-B3B3-6AABA76D7A69-low.gif
Figure 6-5 Offset Voltage vs Temperature
GUID-0F976D19-29DF-46F9-B468-84734ACF4BE5-low.gif
Figure 6-7 Common-Mode Rejection Production Distribution A2
GUID-2348BD6B-FB99-438E-B7CB-AC57D4F2E6D7-low.gif
Figure 6-9 Common-Mode Rejection Production Distribution A4
GUID-D21237FB-54A4-41F7-B66E-A07BCAF00134-low.gif
Figure 6-11 Gain Error Production Distribution A1
GUID-1E6D6517-AD80-44A4-BE89-6985C7B09F57-low.gif
Figure 6-13 Gain Error Production Distribution A3
GUID-EE90F256-8405-433A-B9DD-CBB58D6EDEAF-low.gif
Figure 6-15 Gain Error vs Temperature
GUID-7D0022CD-E1F7-4A1D-9C9D-BAA49E5270CF-low.gif
Figure 6-17 Power-Supply Rejection Ratio vs Frequency
GUID-9238FF7E-BB77-4DF9-B1EF-6DCBAA173830-low.gif
Figure 6-19 Output Voltage Swing vs Output Current
GUID-70DFF281-B21B-4D94-B871-44F2DF7628F9-low.gif
Supply voltage = 0 V
Figure 6-21 Input Bias Current vs Common-Mode Voltage (Both Inputs, Shutdown)
GUID-0D826A7A-60BC-4D42-95B7-5B8D74EF2684-low.gif
Figure 6-23 Quiescent Current vs Temperature (INA181)
GUID-D670353F-C05E-4594-A0AE-E5AB9F1789AB-low.gif
Figure 6-25 Quiescent Current vs Temperature (INA4181)
GUID-99C84BAF-F322-44A1-978A-258B0FC70513-low.gif
Figure 6-27 IQ vs Common-Mode Voltage (INA2181)
GUID-67AD270B-4C0E-4A15-BDC5-554792F2B0CD-low.gif
Figure 6-29 Input-Referred Voltage Noise vs Frequency (A3 Devices)
GUID-9A1E7EC2-ED89-401A-B94E-AFC91E1B68A9-low.gif
80-mVPP input step
Figure 6-31 Step Response
GUID-AA595013-9805-427F-A7A1-F5F8CA35037E-low.gif
Figure 6-33 Inverting Differential Input Overload
GUID-9D6F24AF-019C-4F6B-A556-4B887A4EB084-low.gif
Figure 6-35 Start-Up Response
GUID-9BA242E6-087D-45D3-A079-212CC0DD69C3-low.gif
Figure 6-37 Output Impedance vs Frequency
GUID-B3161A5E-F3B1-4D11-9DD8-ACA2869C673A-low.gif
Figure 6-2 Input Offset Voltage Production Distribution A2
GUID-15868F8A-8B11-434B-B96D-616047C16AC5-low.gif
Figure 6-4 Input Offset Voltage Production Distribution A4
GUID-90F38F45-9184-4D97-AEAD-95C00B62C52F-low.gif
Figure 6-6 Common-Mode Rejection Production Distribution A1
GUID-21602504-9BD5-4441-A1DA-EEC71CDEE8BB-low.gif
Figure 6-8 Common-Mode Rejection Production Distribution A3
GUID-4C097807-66E1-4635-A028-FB6555FD0A91-low.gif
Figure 6-10 Common-Mode Rejection Ratio vs Temperature
GUID-74315D0A-AD77-4BD0-8E1E-B0B8C4A79C94-low.gif
Figure 6-12 Gain Error Production Distribution A2
GUID-68431509-9319-4133-85E9-5F3873E6AC02-low.gif
Figure 6-14 Gain Error Production Distribution A4
GUID-C319EFC8-0953-4D74-8DC4-2F86235C8B2C-low.gif
Figure 6-16 Gain vs Frequency
GUID-ACB985AB-09E6-474E-8565-7CA667101F60-low.gif
Figure 6-18 Common-Mode Rejection Ratio vs Frequency
GUID-8B3E0759-9F7D-4FEA-8530-4417A0D816F4-low.gif
Supply voltage = 5 V
Figure 6-20 Input Bias Current vs Common-Mode Voltage
GUID-1A611409-296A-484F-995C-C7E499FC0061-low.gif
Figure 6-22 Input Bias Current vs Temperature
GUID-D7A1904C-10D7-4BD1-9981-2FA65795657F-low.gif
Figure 6-24 Quiescent Current vs Temperature (INA2181)
GUID-8B054D09-F625-4531-9F2A-C4C3A97982FE-low.gif
Figure 6-26 IQ vs Common-Mode Voltage (INA181)
GUID-B4D5A70E-3352-4BD9-B13A-D6ED9FFC3FD8-low.gif
Figure 6-28 IQ vs Common-Mode Voltage (INA4181)
GUID-50E465F0-2FC5-4795-8BC4-54DC246BB762-low.gif
Figure 6-30 0.1-Hz to 10-Hz Voltage Noise (Referred-to-Input)
GUID-3A578667-A789-4949-990B-67E394F246F0-low.gif
Figure 6-32 Common-Mode Voltage Transient Response
GUID-D2F13C0A-E148-4DFA-99F4-C48683A2CB97-low.gif
Figure 6-34 Noninverting Differential Input Overload
GUID-6DBD8888-35E7-48FF-A1CA-A69E2F7A8A4C-low.gif
Figure 6-36 Brownout Recovery
GUID-A8C3AC6C-A305-4617-AD56-F21EB0F5C8C7-low.gif
Figure 6-38 Channel Separation vs Frequency (INA2181)

 
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