DLPS021 September   2019 DLP470TP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application (LED Configuration)
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  Storage Conditions
    3. 6.3  ESD Ratings
    4. 6.4  Recommended Operating Conditions
    5. 6.5  Thermal Information
    6. 6.6  Electrical Characteristics
    7. 6.7  Capacitance at Recommended Operating Conditions
    8. 6.8  Timing Requirements
    9. 6.9  System Mounting Interface Loads
    10. 6.10 Micromirror Array Physical Characteristics
    11. 6.11 Micromirror Array Optical Characteristics
    12. 6.12 Window Characteristics
    13. 6.13 Chipset Component Usage Specification
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Power Interface
      2. 7.3.2 Timing
    4. 7.4 Device Functional Modes
    5. 7.5 Optical Interface and System Image Quality Considerations
      1. 7.5.1 Numerical Aperture and Stray Light Control
      2. 7.5.2 Pupil Match
      3. 7.5.3 Illumination Overfill
    6. 7.6 Micromirror Array Temperature Calculation
    7. 7.7 Micromirror Landed-On/Landed-Off Duty Cycle
      1. 7.7.1 Definition of Micromirror Landed-On/Landed-Off Duty Cycle
      2. 7.7.2 Landed Duty Cycle and Useful Life of the DMD
      3. 7.7.3 Landed Duty Cycle and Operational DMD Temperature
      4. 7.7.4 Estimating the Long-Term Average Landed Duty Cycle of a Product or Application
  8. 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 Temperature Sensor Diode
  9. 9 Power Supply Recommendations
    1. 9.1 DMD Power Supply Power-Up Procedure
    2. 9.2 DMD Power Supply Power-Down Procedure
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
      1. 10.2.1 Layers
      2. 10.2.2 Impedance Requirements
      3. 10.2.3 Trace Width, Spacing
        1. 10.2.3.1 Voltage Signals
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Device Nomenclature
      2. 11.1.2 Device Markings
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.6 Micromirror Array Temperature Calculation

DLP470TP DS-47-4K-s316-Temp.gifFigure 10. DMD Thermal Test Points

Micromirror array temperature cannot be measured directly, therefore it must be computed analytically from measurement points on the outside of the package, the package thermal resistance, the electrical power, and the illumination heat load. The relationship between array temperature and the reference ceramic temperature (thermal test TP1 in Figure 10) is provided by the following equations:

TARRAY = TCERAMIC + (QARRAY × RARRAY-TO-CERAMIC)
QARRAY = QELECTRICAL + QILLUMINATION

where

  • TARRAY = Computed array temperature (°C)
  • TCERAMIC = Measured ceramic temperature (°C) (TP1 location)
  • RARRAY-TO-CERAMIC = Thermal resistance of package specified in Thermal Information from array to ceramic TP1 (°C/Watt)
  • QARRAY = Total (electrical + absorbed) DMD power on the array (Watts)
  • QELECTRICAL = Nominal electrical power
  • QILLUMINATION = (CL2W × SL)
  • CL2W = Conversion constant for screen lumens to power on DMD (Watts/Lumen)
  • SL = Measured screen Lumens

The electrical power dissipation of the DMD is variable and depends on the voltages, data rates, and operating frequencies. A nominal electrical power dissipation to use when calculating array temperature is 1.3 W. The absorbed power from the illumination source is variable and depends on the operating state of the micromirrors and the intensity of the light source. The equations shown above are valid for a 1-chip DMD system with projection efficiency from the DMD to the screen of 87%.

The conversion constant CL2W is calculated to be 0.00266 W/lm based on array characteristics. It assumes a spectral efficiency of 300 lumens/Watt for the projected light and illumination distribution of 83.7% on the active array, and 16.3% on the array border.

A sample calculation for a typical projection application is as follows:

SL = 1500 lm (measured)
TCERAMIC = 55.0°C (measured)
CL2W = 0.00266 W/lm
QELECTRICAL = 1.3 W
QARRAY = 1.3 W + (0.00266 W/lm × 1500 lm) = 5.29 W
TARRAY = 55.0°C + (5.29 W × 1.2°C/W) = 61.35°C