Si4944DY_RC Vishay Siliconix R-C Thermal Model Parameters DESCRIPTION The parametric values in the R-C thermal model have been derived using curve-fitting techniques. These techniques are described in "A Simple Method of Generating Thermal Models for a Power MOSFET"[1]. When implemented in P-Spice, these values have matching characteristic curves to the Single Pulse Transient Thermal Impedance curves for the MOSFET. R-C values for the electrical circuit in the Foster/Tank and Cauer/Filter configurations are included. Note: For a detailed explanation of implementing these values in P-SPICE, refer to Application Note AN609 Thermal Simulations Of Power MOSFETs on P-SPICE Platform. R-C THERMAL MODEL FOR TANK CONFIGURATION R-C VALUES FOR TANK CONFIGURATION Thermal Resistance (°C/W) Junction to Ambient Case Foot RT1 23.2265 N/A 5.7631 RT2 6.7205 N/A 952.9893 m RT3 17.0899 N/A 6.3869 RT4 48.3259 N/A 11.8993 Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CT1 23.8003 m N/A 27.8936 m CT2 10.3117 m N/A 3.3650 m CT3 206.2464 m N/A 11.0918 m CT4 1.4544 N/A 118.7165 m This document is intended as a SPICE modeling guideline and does not constitute a commercial product data sheet. Designers should refer to the appropriate data sheet of the same number for guaranteed specification limits. Document Number: 70381 Revision 19-Mar-07 www.vishay.com 1 Si4944DY_RC Vishay Siliconix R-C THERMAL MODEL FOR FILTER CONFIGURATION R-C VALUES FOR FILTER CONFIGURATION Thermal Resistance (°C/W) Junction to Ambient Case Foot RF1 11.7111 N/A 3.8466 RF2 20.5960 N/A 10.6704 RF3 18.4481 N/A 10.0777 RF4 44.1841 N/A 406.9401 m Junction to Ambient Thermal Capacitance (Joules/°C) Case Foot CF1 7.2348 m N/A 3.4863 m CF2 12.3323 m N/A 6.4665 m CF3 131.5624 m N/A 112.5067 m CF4 1.3255 N/A 906.6078 m Note: NA indicates not applicable Reference: [1] "A Simple Method of Generating Thermal Models for a Power MOSFET" by Wharton McDaniel and Kandarp Pandya, IEEE / SEMITHERM 2002 www.vishay.com 2 Document Number: 70381 Revision 19-Mar-07 Si4944DY_RC Vishay Siliconix Document Number: 70381 Revision 19-Mar-07 www.vishay.com 3