JAJSGU1B January   2019  – May 2022

PRODUCTION DATA

1. 特長
2. アプリケーション
3. 概要
4. Revision History
5. Chipset Component Usage Specification
6. Pin Configuration and Functions
7. Specifications
8. Detailed Description
1. 8.1 Overview
2. 8.2 Functional Block Diagram
3. 8.3 Feature Description
4. 8.4 Device Functional Modes
5. 8.5 Micromirror Array Temperature Calculation
1. 8.5.1 Package Thermal Resistance
2. 8.5.2 Case Temperature
6. 8.6 Micromirror Landed-on/Landed-Off Duty Cycle
9. Applications and Implementation
1. 9.1 Application Information
2. 9.2 Typical Application
1. 9.2.1 Design Requirements
2. 9.2.2 Detailed Design Procedure
1. 9.2.2.1 DLPC350 System Interfaces
2. 9.2.2.2 DLPC350 System Output Interfaces
3. 9.2.2.3 DLPC350 System Support Interfaces
4. 9.2.2.4 DMD Interfaces
10. 10Power Supply Recommendations
11. 11Layout
1. 11.1 Layout Guidelines
2. 11.2 Layout Example
12. 12Device and Documentation Support
13. 13Mechanical, Packaging, and Orderable Information

• FQD|98

#### 8.5.2.1 Temperature Calculation

Micromirror array temperature cannot be measured directly, therefore it must be computed analytically using one or more of these conditions:

• Thermal test point location (see or Figure 8-3)
• Package thermal resistance
• Electrical power dissipation

The relationship between the micromirror array and the case temperature is provided by the following equations:

Equation 1. TArray = TCeramic + (QArray × RArray-To-Ceramic)
Equation 2. QArray = QElec + QIllum
Equation 3. QIllum =  PD × A × DMD Absorption Constant 

where

• TArray = Computed micromirror array temperature (°C)
• TCeramic = Ceramic case temperature (°C), located at TP1
• QArray = Total (electrical + absorbed) DMD array power (W)
• RArray-to-Ceramic = Thermal resistance of DMD package from array to TP1 (°C/W)
• QElec = Nominal electrical power (W)
• QIllum = Absorbed illumination heat (W)
•  PD = Illumination power density 
•  A = Illumination area on DMD 

An example calculation is provided in Equation 4 and Equation 5. DMD electrical power dissipation varies and depends on the voltage, data rates, and operating frequencies. The nominal electrical power dissipation is used in this calculation  with a power density of 2 W/cm2, an illumination area of 0.725 cm2, and a ceramic case temperature at TP1 of 55°C. The DMD absorption constant of 0.42 assumes nominal operation with an illumination distribution of 83.7% on the active array, 11.9% on the array border, and 4.4% on the window aperture. A system aperture may be required to limit power incident on the package aperture since this area absorbs much more efficiently than the array . Using these values in the previous equations, the following values are computed:

Equation 4. QArray = QElec + QIllum = 0.442 W + (2 W/cm2 × 0.725 cm2 × 0.42) = 1.05 W 
Equation 5. TArray = TCeramic + (QArray × RArray-To-Ceramic) = 55°C + (  1.05 W  × 2°C/W) = 57.1°C