SLPS574B February   2016  – April 2018 CSD87335Q3D

PRODUCTION DATA.  

  1. 1Features
  2. 2Applications
  3. 3Description
    1.     Top View
      1.      Device Images
  4. 4Revision History
  5. 5Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 Recommended Operating Conditions
    3. 5.3 Thermal Information
    4. 5.4 Power Block Performance
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Power Block Device Characteristics
    7. 5.7 Typical Power Block MOSFET Characteristics
  6. 6Applications and Implementation
    1. 6.1 Application Information
      1. 6.1.1 Equivalent System Performance
    2. 6.2 Power Loss Curves
    3. 6.3 Safe Operating Curves (SOA)
    4. 6.4 Normalized Curves
    5. 6.5 Calculating Power Loss and SOA
      1. 6.5.1 Design Example
      2. 6.5.2 Calculating Power Loss
      3. 6.5.3 Calculating SOA Adjustments
  7. 7Recommended PCB Design Overview
    1. 7.1 Electrical Performance
    2. 7.2 Thermal Performance
  8. 8Device and Documentation Support
    1. 8.1 Receiving Notification of Documentation Updates
    2. 8.2 Community Resources
    3. 8.3 Trademarks
    4. 8.4 Electrostatic Discharge Caution
    5. 8.5 Glossary
  9. 9Mechanical, Packaging, and Orderable Information
    1. 9.1 Q3D Package Dimensions
    2. 9.2 Land Pattern Recommendation
    3. 9.3 Stencil Recommendation
    4. 9.4 Q3D Tape and Reel Information
    5. 9.5 Pin Configuration

Package Options

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

6.5.3 Calculating SOA Adjustments

  • SOA adjustment for input voltage ≈ 0.14°C (Figure 6)
  • SOA adjustment for output voltage ≈ 0.17°C (Figure 7)
  • SOA adjustment for switching frequency ≈ 1.32°C (Figure 5)
  • SOA adjustment for output inductor ≈ 0.18°C (Figure 8)
  • Final calculated SOA adjustment = 0.14 + 0.17 + 1.32 + 0.18 ≈ 1.81°C

In the design example above, the estimated power loss of the CSD87335Q3D would increase to 2.14 W. In addition, the maximum allowable board and/or ambient temperature would have to decrease by 1.81°C. Figure 32 graphically shows how the SOA curve would be adjusted accordingly.

  1. Start by drawing a horizontal line from the application current to the SOA curve.
  2. Draw a vertical line from the SOA curve intercept down to the board/ambient temperature.
  3. Adjust the SOA board/ambient temperature by subtracting the temperature adjustment value.

In the design example, the SOA temperature adjustment yields a reduction in allowable board/ambient temperature of 1.81°C. In the event the adjustment value is a negative number, subtracting the negative number would yield an increase in allowable board/ambient temperature.

CSD87335Q3D D033_SLPS574_r2.pngFigure 32. Power Block SOA