SCAS898C May   2010  – May 2026 CDCLVD1204

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 LVDS Output Termination
      2. 7.4.2 Input Termination
  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
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Thermal Considerations
  12. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  13. 12Revision History
  14. 13Mechanical, Packaging, and Orderable Information

10.3 Thermal Considerations

The CDCLVD1204 supports high temperatures on the printed circuit board (PCB) measured at the thermal pad. The system designer must ensure that the maximum junction temperature is not exceeded. ΨJB can allow the system designer to measure the board temperature with a fine gauge thermocouple and back calculate the junction temperature using Equation 1. Note that ΨJB is close to RθJB as 75% to 95% of a device's heat is dissipated by the PCB.

Equation 1. TJ = TPCB + ( ΨJB × Power)
Example:
Calculation of the junction-lead temperature with a 4-layer JEDEC test board using four thermal vias:
TPCB = 105°C
ΨJB = 19.4°C/W
PowerinclTerm = Imax × Vmax = 80 mA × 2.625 V = 210 mW (maximum power consumption including termination resistors)
PowerexclTerm = 202 mW (maximum power consumption excluding termination resistors, see Power Consumption of LVPECL and LVDS (SLYT127) for further details)
ΔTJ = ΨJB × PowerexclTerm = 19.4°C/W × 202 mW = 3.92°C
TJ = ΔTJ + TChassis = 3.92°C + 105°C = 108.92°C (maximum junction temperature of 125°C is not violated)

Further information can be found at Semiconductor and IC Package Thermal Metrics (SPRA953) and Using Thermal Calculation Tools for Analog Components (SLUA566).