SLVSE16E May   2019  – September 2026 TPS1HB08-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
    1. 5.1 Recommended Connections for Unused Pins
  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 SNS Timing Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 Typical Characteristics
  8. 7 Parameter Measurement Information
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Protection Mechanisms
        1. 8.3.1.1 Thermal Shutdown
        2. 8.3.1.2 Current Limit
          1. 8.3.1.2.1 Current Limit Foldback
          2. 8.3.1.2.2 Programmable Current Limit
          3. 8.3.1.2.3 Undervoltage Lockout (UVLO)
          4. 8.3.1.2.4 VBB During Short-to-Ground
        3. 8.3.1.3 Voltage Transients
          1. 8.3.1.3.1 Load Dump
          2. 8.3.1.3.2 Driving Inductive Loads
        4. 8.3.1.4 Reverse Battery
        5. 8.3.1.5 Fault Event – Timing Diagrams - Version A and B
        6. 8.3.1.6 Fault Event – Timing Diagrams - Version F
      2. 8.3.2 Diagnostic Mechanisms
        1. 8.3.2.1 VOUT Short-to-Battery and Open-Load
          1. 8.3.2.1.1 Detection With Switch Enabled
          2. 8.3.2.1.2 Detection With Switch Disabled
        2. 8.3.2.2 SNS Output
          1. 8.3.2.2.1 RSNS Value
            1. 8.3.2.2.1.1 High Accuracy Load Current Sense
            2. 8.3.2.2.1.2 SNS Output Filter
        3. 8.3.2.3 Fault Indication and SNS Mux
        4. 8.3.2.4 Resistor Sharing
        5. 8.3.2.5 High-Frequency, Low Duty-Cycle Current Sensing
    4. 8.4 Device Functional Modes
      1. 8.4.1 Off
      2. 8.4.2 Standby
      3. 8.4.3 Diagnostic
      4. 8.4.4 Standby Delay
      5. 8.4.5 Active
      6. 8.4.6 Fault
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Ground Protection Network
      2. 9.1.2 Interface With Microcontroller
      3. 9.1.3 I/O Protection
      4. 9.1.4 Inverse Current
      5. 9.1.5 Loss of GND
      6. 9.1.6 Automotive Standards
        1. 9.1.6.1 ISO7637-2
        2. 9.1.6.2 TPS1HB08-Q1 AEC-Q100-012 Short-Circuit Reliability
      7. 9.1.7 Interference on Device Pins
      8. 9.1.8 Thermal Information
    2. 9.2 Typical Application: Resistive Heater Loads
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Thermal Considerations
        2. 9.2.2.2 RILIM Calculation
        3. 9.2.2.3 Diagnostics
          1. 9.2.2.3.1 Selecting the RISNS Value
    3. 9.3 Typical Application: Headlight Bulb Loads
      1. 9.3.1 Design Requirements
      2. 9.3.2 Detailed Design Procedure
      3. 9.3.3 Application Curves
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

9.2.2.1 Thermal Considerations

The 130 W heater load causes a DC current in the channel under maximum load power condition of around 9.6 A. Therefore, this current at 13.5V assumes worst-case heating.

Power dissipation in the switch is calculated in Equation 4. RON is assumed to be 16 mΩ because this is the maximum specification at high temperature. In practice, RON is almost always lower.

Equation 4. PFET = I2 × RON
Equation 5. PFET = (9.6A)2 × 16mΩ = 1.47W

This means that the maximum FET power dissipation is 1.47 W. The junction temperature of the device can be calculated using Equation 6 and the RθJA value from the Specifications section.

Equation 6. TJ = TA + RθJA × PFET
TJ = 70°C + 32.6°C/W × 1.47W = 117.9°C

The maximum junction temperature rating for the TPS1HB08-Q1 is TJ = 150°C. Based on the above example calculation, the device temperature stays below the maximum rating even at this high level of current.