JAJSEX6B December   2017  – October 2019 INA381

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      代表的なアプリケーション
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Wide Input Common-Mode Voltage Range
      2. 8.3.2 Precise Low-Side Current Sensing
      3. 8.3.3 High Bandwidth and Slew Rate
      4. 8.3.4 Alert Output
      5. 8.3.5 Adjustable Overcurrent Threshold
      6. 8.3.6 Comparator Hysteresis
    4. 8.4 Device Functional Modes
      1. 8.4.1 Alert Modes
        1. 8.4.1.1 Transparent Output Mode
        2. 8.4.1.2 Latch Output Mode
  9. 9 Applications and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Select a Current-Sensing Resistor
        1. 9.1.1.1 Select a Current-Sensing Resistor: Example
      2. 9.1.2 Increase Comparator Hysteresis
      3. 9.1.3 Operation With Common-Mode Transients Greater Than 26 V
      4. 9.1.4 Input Filtering
    2. 9.2 Typical Applications
      1. 9.2.1 Bidirectional Window Comparator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
        3. 9.2.1.3 Application Curve
      2. 9.2.2 Solenoid Low-Side Current Sensing
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 ドキュメントのサポート
      1. 12.1.1 関連資料
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 サポート・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報

パッケージ・オプション

デバイスごとのパッケージ図は、PDF版データシートをご参照ください。

メカニカル・データ（パッケージ｜ピン）
  • DGS|10
  • DSG|8
サーマルパッド・メカニカル・データ
発注情報

9.1.1.1 Select a Current-Sensing Resistor: Example

In this example, the trade-offs involved in selecting a current-sensing resistor are discussed. This example requires 5% accuracy for detecting a 10-A overcurrent event under 20 µs where only 250 mW is allowable for the 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 to improve system efficiency. Given the total error budget of 5%, the INA381 total error is less than 1%. The INA381 is well suited for this application because up to 1% of error is available to be attributed to the measurement error of the device under these conditions.

As shown in Table 2, 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 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% and still remaining within the accuracy region.

Table 2. 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, VCM = 12 V 500 µV
VOS_ERROR Initial offset voltage error (VOS / (RSENSE_MAX × IMAX ) × 100 2%
EG Gain error 1%
ERRORTOTAL Total measurement error √(VOS_ERROR2 + EG2) 2.23%
Allowable current threshold accuracy 5%
tp Total system overcurrent response time 10 µs
Allowable overcurrent response 20 µs