SLVSHS0C March   2025  – September 2026 TPS482H85-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
  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 24V
    8. 6.8 Switching Characteristics 48V
    9. 6.9 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Pin Current and Voltage Conventions
      2. 7.3.2 Accurate Current Sense
      3. 7.3.3 Adjustable Current Limit
        1. 7.3.3.1 Short-Circuit Reliability
      4. 7.3.4 Inductive-Load Switching-Off Clamp
      5. 7.3.5 Fault Detection and Reporting
        1. 7.3.5.1 Diagnostic Enable Function
        2. 7.3.5.2 Multiplexing of Current Sense
        3. 7.3.5.3 FLT Reporting
        4. 7.3.5.4 Fault Table
      6. 7.3.6 Full Diagnostics
        1. 7.3.6.1 Short-to-GND and Overload Detection
        2. 7.3.6.2 Open-Load Detection
          1. 7.3.6.2.1 Channel On
          2. 7.3.6.2.2 Channel Off
        3. 7.3.6.3 Short-to-Battery Detection
        4. 7.3.6.4 Reverse-Polarity and Battery Protection
        5. 7.3.6.5 Thermal Fault Detection
          1. 7.3.6.5.1 Thermal Protection Behavior
      7. 7.3.7 Full Protections
        1. 7.3.7.1 UVLO Protection
        2. 7.3.7.2 Loss of GND Protection
        3. 7.3.7.3 Loss of Power Supply Protection
        4. 7.3.7.4 Loss of VDD
        5. 7.3.7.5 Reverse Current Protection
        6. 7.3.7.6 Protection for MCU I/Os
    4. 7.4 Device Functional Modes
      1. 7.4.1 Operational Modes
        1. 7.4.1.1 SLEEP
        2. 7.4.1.2 DIAGNOSTIC
        3. 7.4.1.3 ACTIVE
        4. 7.4.1.4 FAULT
        5. 7.4.1.5 STANDBY DELAY
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Examples
        1. 8.4.2.1 Without a GND Network
        2. 8.4.2.2 With a GND Network
  10. 9 Device and Documentation Support
    1. 9.1 Third-Party Products Disclaimer
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.4 Inductive-Load Switching-Off Clamp

When switching an inductive load off, the inductive reactance tends to pull the output voltage negative. Excessive negative voltage can cause the power FET to break down. To protect the power FET, an internal clamp between drain and source is implemented, namely VDS(clamp).

Equation 2. V DS(damp) = V VS − V OUT

During the period of demagnetization (tdecay), the power FET is turned on for inductance-energy dissipation. The total energy is dissipated in the high-side switch. Total energy includes the energy of the power supply (E(VS)) and the energy of the load (E(load)). If resistance is in series with inductance, some of the load energy is dissipated on the resistance.

Equation 3. E ( H S S ) = E ( V S ) + E ( l o a d ) = E ( V S ) + E ( L ) − E ( R )

When an inductive load switches off, E(HSS) causes high thermal stressing on the device. The upper limit of the power dissipation depends on the device intrinsic capacity, ambient temperature, and board dissipation condition.

TPS482H85-Q1 Drain-to-Source Clamping StructureFigure 7-8 Drain-to-Source Clamping Structure
TPS482H85-Q1 Inductive Load Switching-Off DiagramFigure 7-9 Inductive Load Switching-Off Diagram

From the perspective of the high-side switch, E(HSS) equals the integration value during the demagnetization period.

Equation 4. EHSS=∫0tdecayVDSclamp×IOUTtdttdecay=LR×ln⁡R×IOUTmax+VOUTVOUTEHSS=L×VVS+VOUTR2×R×IOUTmax-VOUTln⁡R×IOUTmax+VOUTVOUT

When R approximately equals zero, E(HSD) is given simply as:

Equation 5. E ( HSS ) = 1 2 × L × I OUT ( max ) 2 V VS + | V OUT | | V OUT |

The device optimizes the switching-off slew rate when the clamp is active. This optimization can help the system design by keeping the effects of transient power and EMI to a minimum. The controlled slew rate is around 0.7V/µs.

The recommendation for PWM-controlled inductive loads is to add the external freewheeling circuitry shown in Figure 7-10 to protect the device from repetitive power stressing. The TVS is used to achieve the fast decay. See Figure 7-10 for more details.

TPS482H85-Q1 Protection With External CircuitryFigure 7-10 Protection With External Circuitry

For the TPS482H85A and B variants, the output voltage rises up during VBB line transient as the VDS clamp is engaged. The TPS482H85C on thee other hand does not engage the clamp during VBB line transients above 58V, but only activates the clamp during inductive energy dissipation. It is important to restrict the VBB to GND voltage to a maximum of 70V as per Section 6.1. All the variants have identical behavior when turning off inductive loads in the recommended VBB nominal voltage range (from 6V to 58V).

TPS482H85-Q1 Inductive Load Switching-Off Differences Between A, B and C Variants Figure 7-11 Inductive Load Switching-Off Differences Between A, B and C Variants