SiR172DP_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 T (Junction) RT1 RT2 RT3 RT4 CT1 CT2 CT3 CT4 T (Ambient) R-C VALUES FOR TANK CONFIGURATION THERMAL RESISTANCE (°C/W) Junction to Ambient Case RT1 4.1445 1.2625 Foot N/A RT2 19.9992 756.0587 m N/A RT3 12.9882 1.6067 N/A RT4 32.4905 568.8167 m N/A Junction to Ambient Case CT1 800.7029 u 9.7047 m N/A CT2 800.4347 m 231.7825 u N/A CT3 44.5832 m 2.7296 m N/A CT4 3.5730 59.9343 m N/A THERMAL CAPACITANCE (Joules/°C) Foot Note N/A indicates not applicable This document is intended as a SPICE modeling guideline and does not constitute a commercial product datasheet. Designers should refer to the appropriate datasheet of the same number for guaranteed specification limits. Document Number: 65469 Revision: 21-Sep-09 www.vishay.com 1 SiR172DP_RC Vishay Siliconix R-C THERMAL MODEL FOR FILTER CONFIGURATION T (Junction) RF2 RF1 CF1 CF2 RF3 RF4 T (Ambient) CF4 CF3 GND R-C VALUES FOR FILTER CONFIGURATION THERMAL RESISTANCE (°C/W) Junction to Ambient Case Foot RF1 4.3843 1.2034 N/A RF2 13.8729 2.5951 N/A RF3 22.4450 355.5178 m N/A RF4 28.7972 36.4413 m N/A THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case Foot CF1 864.4478 u 297.1840 u N/A CF2 40.1066 m 2.7819 m N/A CF3 531.0055 m 66.3246 m N/A CF4 2.7495 31.4831 m N/A Note N/A indicates not applicable www.vishay.com 2 Document Number: 65469 Revision: 21-Sep-09 SiR172DP_RC Vishay Siliconix Document Number: 65469 Revision: 21-Sep-09 www.vishay.com 3