• Menu
  • Product
  • Email
  • PDF
  • Order now

  • INA1x8 High-Side Measurement Current Shunt Monitor

    • SBOS122E December   1999  – December 2017 INA138 , INA168

      PRODUCTION DATA.  

  • CONTENTS
  • SEARCH
  • INA1x8 High-Side Measurement Current Shunt Monitor
  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 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
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Output Voltage Range
      2. 7.3.2 Bandwidth
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Operation
    2. 8.2 Typical Applications
      1. 8.2.1 Buffering Output to Drive an ADC
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Selecting the Shunt Resistor and RL
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Output Filter
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
        3. 8.2.2.3 Application Curve
      3. 8.2.3 Offsetting the Output Voltage
      4. 8.2.4 Bipolar Current Measurement
      5. 8.2.5 Bipolar Current Measurement Using Differential Input of ADC
      6. 8.2.6 Multiplexed Measurement Using Logic Signal for Power
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
  13. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • DBV|5
    • MPDS018T
Thermal pad, mechanical data (Package|Pins)
Orderable Information
  • sbos122e_oa
  • sbos122e_pm
search No matches found.
  • Full reading width
    • Full reading width
    • Comfortable reading width
    • Expanded reading width
  • Card for each section
  • Card with all content

 

DATA SHEET

INA1x8 High-Side Measurement Current Shunt Monitor

1 Features

  • Complete Unipolar High-Side Current Measurement Circuit
  • Wide Supply and Common-Mode Range
  • INA138: 2.7 V to 36 V
  • INA168: 2.7 V to 60 V
  • Independent Supply and Input Common-Mode Voltages
  • Single Resistor Gain Set
  • Low Quiescent Current (25 µA Typical)
  • Wide Temperature Range: –40°C to +125°C
  • 5-Pin SOT-23 Package

2 Applications

  • Current Shunt Measurement:
    • Telephone, Computers
  • Portable and Battery-Backup Systems
  • Battery Chargers
  • Power Management
  • Cell Phones
  • Precision Current Source

3 Description

The INA138 and INA168 (INA1x8) are high-side, unipolar, current shunt monitors. Wide input common-mode voltage range, low quiescent current, and tiny SOT-23 packaging enable use in a variety of applications.

Input common-mode and power-supply voltages are independent and can range from 2.7 V to 36 V for the INA138 and 2.7 V to 60 V for the INA168. Quiescent current is only 25 µA, which permits connecting the power supply to either side of the current measurement shunt with minimal error.

The device converts a differential input voltage to a current output. This current is converted back to a voltage with an external load resistor that sets any gain from 1 to over 100. Although designed for current shunt measurement, the circuit invites creative applications in measurement and level shifting.

Both the INA138 and INA168 are available in SOT23-5 and are specified for the –40°C to 125°C temperature range.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
INA138 SOT-23 (5) 2.90 mm × 1.60 mm
INA168
  1. For all available packages, see the package option addendum at the end of the datasheet.

Typical Application Circuit

INA138 INA168 fiirst_page_sbos122.gif

4 Revision History

Changes from D Revision (December 2014) to E Revision

  • Added reference design link to navigation bar at the top of the front pageGo
  • Changed body size from 18.00 mm × 18.00 mm to 2.90 mm × 1.60 mm in Device Information tableGo
  • Changed pin numbers in pin functions table to match pin configuration figureGo
  • Changed Absolute Maximum Ratings table for clarity; no values were changed Go
  • Changed Recommended Operating Conditions table; moved some content from Electrical Characteristics table, but no values changedGo
  • Changed all values in Thermal Information tableGo
  • Changed Electrical Characteristics table; reformatted for clarity; moved some content to Recommended Operating Conditions table, and deleted duplicate contentGo
  • Changed common-mode rejection test conditions to better highlight each device in Electrical Characteristics table Go
  • Changed offset voltage vs temperature to offset voltage drift in Electrical Characteristics tableGo
  • Changed offset voltage vs power supply test conditions to better highlight each device in Electrical Characteristics tableGo
  • Changed reference in text from Figure 10 to Figure 11 in last paragraph of Selecting the Shunt Resistor and RL sectionGo

Changes from C Revision (November 2005) to D Revision

  • Added ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section. Go

5 Pin Configuration and Functions

DBV Package
5-Pin SOT-23
Top View

Pin Functions

PIN I/O DESCRIPTION
NO. NAME
1 OUT O Output current
2 GND — Ground
3 VIN+ I Positive input voltage
4 VIN– I Negative input voltage
5 V+ I Power supply voltage

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted) (1)
MIN MAX UNIT
Voltage Supply, V+ INA138 –0.3 60 V
INA168 –0.3 75
Analog input, VIN+, VIN– INA138 Common mode(2) –0.3 60
Sense voltage, VSENSE = (VIN+ – VIN–) –40 2
INA168 Common mode(2) –0.3 75
Sense voltage, VSENSE = (VIN+ – VIN–) –40 2
Analog output, OUT pin(2) –0.3 40
Current Input current into any pin 10 mA
Temperature Operating, TA –55 150 °C
Junction, TJ 150
Storage, Tstg –65 150
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
(2) The input voltage at any pin may exceed the voltage shown if the current at that pin is limited to 10 mA.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) ±1000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) ±500
(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
INA138
V+ Supply voltage 2.7 5 36 V
VSENSE Full-scale sense voltage (VIN+ – VIN–) 100 500 mV
Common-mode voltage 2.7 12 36 V
TA Operating temperature –40 25 125 °C
INA168
V+ Supply voltage 2.7 5 60 V
VSENSE Full-scale sense voltage (VIN+ – VIN–) 100 500 mV
Common-mode voltage 2.7 12 60 V
TA Operating temperature –40 25 125 °C

6.4 Thermal Information

THERMAL METRIC(1) INA1x8 UNIT
DBV
5 PINS
RθJA Junction-to-ambient thermal resistance 168.3 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 73.8 °C/W
RθJB Junction-to-board thermal resistance 28.1 °C/W
ψJT Junction-to-top characterization parameter 2.5 °C/W
ψJB Junction-to-board characterization parameter 27.6 °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

all other characteristics at TA = +25°C, VS = 5 V, VIN+ = 12 V, and ROUT = 125 kΩ (unless otherwise noted)
PARAMETER TEST CONDITIONS INA1x8 UNIT
MIN TYP MAX
INPUT
Common-mode rejection VSENSE = 50 mV INA138, VIN+ = 2.7 V to 36 V 100 120 dB
INA168, VIN+ = 2.7 V to 60 V 100 120
Offset voltage(1) TA = 25°C ±0.2 ±1 mV
TA = –40°C to +125°C ±2
Offset voltage drift(1) TA = –40°C to +125°C 1 µV/°C
Offset voltage vs power supply, V+ VSENSE = 50 mV INA138, V+ = 2.7 V to 36 V 0.1 10 µV/V
INA168, V+ = 2.7 V to 60 V 0.1 10
Input bias current TA = 25°C 2 µA
TA = –40°C to +125°C, INA138 10
OUTPUT
Transconductance VSENSE = 10 mV to 150 mV, TA = 25°C 198 200 202 µA/V
VSENSE = 100 mV, TA = –40°C to +125°C 196 204 µA/V
Transconductance drift TA = –40°C to +125°C 10 nA/°C
Nonlinearity error VSENSE = 10 mV to 150 mV ±0.01% ±0.1%
Total output error VSENSE = 100 mV TA = 25°C ±0.5% ±2%
TA = –40°C to +125°C ±2.5%
Output impedance 1 || 5 GΩ || pF
Voltage output swing To power supply voltage, V+ (V+) – 0.8 (V+) – 1.0 V
To common-mode voltage, VCM VCM – 0.5 VCM – 0.8 V
FREQUENCY RESPONSE
Bandwidth ROUT = 5 kΩ 800 kHz
ROUT = 125 kΩ 32 kHz
Settling time To 0.1% 5-V step, ROUT = 5 kΩ 1.8 µs
5-V step, ROUT = 125 kΩ 30 µs
NOISE
Output-current noise density 9 pA/√Hz
Total output-current noise BW = 100 kHz 3 nA RMS
POWER SUPPLY
Quiescent current VSENSE = 0 V,
IO = 0 mA		 TA = 25°C 25 45 µA
TA = –40°C to +125°C 60 µA
(1) Defined as the amount of input voltage, VSENSE, to drive the output to zero.

6.6 Typical Characteristics

At TA = +25°C, V+ = 5 V, VIN+ = 12 V, and RL = 125 kΩ, unless otherwise noted.
INA138 INA168 graph_1_sbos122.gif
Figure 1. Gain vs Frequency
INA138 INA168 graph_3_sbos122.gif
Figure 3. Power-Supply Rejection vs Frequency
INA138 INA168 graph_5_sbos122.gif
Figure 5. Total Output Error vs Power-Supply Voltage
INA138 INA168 g_stepresp01_gls174.gif
Figure 7. Step Response
INA138 INA168 graph_2_sbos122.gif
Figure 2. Common-Mode Rejection vs Frequency
INA138 INA168 graph_4_sbos122.gif
Figure 4. Total Output Error vs VIN
INA138 INA168 graph_6_sbos122.gif
Figure 6. Quiescent Current vs Power-Supply Voltage
INA138 INA168 g_stepresp02_gls174.gif
Figure 8. Step Response

7 Detailed Description

7.1 Overview

The INA138 and INA168 devices (INA1x8) are comprised of a high voltage, precision operational amplifier, precision thin film resistors trimmed in production to an absolute tolerance and a low noise output transistor. The INA1x8 devices can be powered from a single power supply and their input voltages can exceed the power supply voltage. The INA1x8 devices are ideal for measuring small differential voltages, such as those generated across a shunt resistor, in the presence of large common-mode voltages. Refer to Functional Block Diagram which illustrates the functional components within both INA1x8 devices.

7.2 Functional Block Diagram

INA138 INA168 SBD_SBOS122.gif

7.3 Feature Description

7.3.1 Output Voltage Range

The output of the INA1x8 device is a current that is converted to a voltage by the load resistor, RL. The output current remains accurate within the compliance voltage range of the output circuitry. The shunt voltage and the input common-mode and power-supply voltages limit the maximum possible output swing. The maximum output voltage (Vout max) compliance is limited by either Equation 1 or Equation 2, whichever is lower:

Equation 1. Vout max = (V+) – 0.7 V – (VIN+ – VIN–)

or

Equation 2. Vout max = VIN– – 0.5 V

7.3.2 Bandwidth

Measurement bandwidth is affected by the value of the load resistor, RL. High gain produced by high values of RL will yield a narrower measurement bandwidth (see Typical Characteristics). For widest possible bandwidth, keep the capacitive load on the output to a minimum. Reduction in bandwidth due to capacitive load is shown in the Typical Characteristics.

If bandwidth limiting (filtering) is desired, a capacitor can be added to the output (see Figure 12). This will not cause instability.

7.4 Device Functional Modes

For proper operation the INA1x8 devices must operate within their specified limits. Operating either device outside of their specified power supply voltage range or their specified common-mode range will result in unexpected behavior and is not recommended. Additionally operating the output beyond their specified limits with respect to power supply voltage and input common-mode voltage will also produce unexpected results. Refer to Electrical Characteristics for the device specifications.

 
Texas Instruments

© Copyright 1995-2025 Texas Instruments Incorporated. All rights reserved.
Submit documentation feedback | IMPORTANT NOTICE | Trademarks | Privacy policy | Cookie policy | Terms of use | Terms of sale