Si8445DB_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. R-C values for the electrical circuit in the Foster/Tank and Cauer/Filter configurations are included. When implemented in P-SPICE, these values have matching characteristic curves to the single-pulse transient thermal impedance curves for the MOSFET. These RC values can be used in the P-SPICE simulation to evaluate the thermal behavior of the MOSFET junction temperature under a defined power profile. These techniques are described in Application Note AN609, "Thermal Simulation of Power MOSFETs on the 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 13.7828 2.4018 N/A RT2 34.1395 6.8064 N/A RT3 10.2674 468.2439 m N/A RT4 41.8103 1.4250 N/A Thermal Capacitance (Joules/°C) Case Foot 266.3948 u 68.0774 u N/A 1.1738 m 397.5839 u N/A CT3 123.6454 m 111.1075 m N/A CT4 1.2506 1.6817 m N/A Junction to Ambient CT1 CT2 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: 68659 Revision: 11-Apr-08 www.vishay.com 1 Si8445DB_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 21.3540 3.2599 N/A RF2 26.9020 7.0261 N/A RF3 11.5156 487.5123 m N/A RF4 40.2284 226.4877 m N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 CF2 232.6465 u 55.6486 u N/A 1.1494 m 261.4637 u N/A CF3 98.9079 m 10.6946 m N/A CF4 1.1750 802.5108 u N/A Note: NA indicates not applicable www.vishay.com 2 Document Number: 68659 Revision: 11-Apr-08 Si8445DB_RC Vishay Siliconix Document Number: 68659 Revision: 11-Apr-08 www.vishay.com 3