SBOS786B April   2016  – April 2022 INA301-Q1

PRODUCTION DATA  

  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 Alert Output ( ALERT Pin)
      2. 7.3.2 Current-Limit Threshold
        1. 7.3.2.1 Resistor-Controlled Current Limit
          1. 7.3.2.1.1 Resistor-Controlled, Current-Limit Example
        2. 7.3.2.2 Voltage-Source-Controlled Current Limit
      3. 7.3.3 Hysteresis
    4. 7.4 Device Functional Modes
      1. 7.4.1 Alert Mode
        1. 7.4.1.1 Transparent Output Mode
        2. 7.4.1.2 Latch Output Mode
  8. 8 Applications and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Selecting a Current-Sensing Resistor
        1. 8.1.1.1 Selecting a Current-Sensing Resistor Example
      2. 8.1.2 Input Filtering
      3. 8.1.3 INA301-Q1 Operation With Common-Mode Voltage Transients Greater Than 36 V
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curve
  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 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.1.1.1 Selecting a Current-Sensing Resistor Example

In this example, the trade-offs involved in selecting a current-sensing resistor are described. This example requires 2.5% accuracy for detecting a 10-A overcurrent event, with only 250 mW of allowable power dissipation across the current-sensing resistor at the full-scale current level. Although the maximum power dissipation is defined as 250 mW, a lower dissipation is preferred in order to improve system efficiency. Some initial assumptions are made that are used in this example:

  • the limit-setting resistor (RLIMIT) is a 1% component
  • the maximum tolerance specification for the internal threshold setting current source (0.5%) is used

Given the total error budget of 2.5%, up to 1% of error is available to be attributed to the measurement error of the device under these conditions.

As shown in Table 8-1, the maximum value calculated for the current-sensing resistor with these requirements is 2.5 mΩ. Although this value satisfies the maximum power dissipation requirement of 250 mW, headroom is available from the 2.5% maximum total overcurrent detection error in order to reduce the value of the current-sensing resistor, and reduce the power dissipation further. Selecting a 1.5-mΩ, current-sensing resistor value offers a good tradeoff for reducing the power dissipation in this scenario by approximately 40% while still remaining within the accuracy region.

Table 8-1 Calculating the Current-Sensing Resistor, RSENSE
PARAMETER EQUATION VALUE UNIT
IMAX Maximum current 10 A
PD_MAX Maximum allowable power dissipation 250 mW
RSENSE_MAX Maximum allowable RSENSE PD_MAX / IMAX2 2.5 mΩ
VOS Offset voltage 150 µV
VOS_ERROR Initial offset voltage error (VOS / (RSENSE_MAX × IMAX ) × 100 0.6%
EG Gain error 0.25%
ERRORTOTAL Total measurement error √(VOS_ERROR2 + EG2) 0.65%
Allowable current threshold accuracy 2.5%
ERRORINITIAL Initial threshold error ILIMIT Tolerance + RLIMIT Tolerance 1.5%
ERRORAVAILABLE Maximum allowable measurement error Maximum Error – ERRORINITIAL 1%
VOS_ERROR_MAX Maximum allowable offset error √(ERRORAVAILABLE2 – EG2) 0.97%
VDIFF_MIN Minimum differential voltage VOS / VOS_ERROR_MAX (1%) 15 mV
RSENSE_MIN Minimum sense resistor value VDIFF_MIN / IMAX 1.5 mΩ
PD_MIN Minimum power dissipation RSENSE_MIN × IMAX2 150 mW