SQ1421EEH_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 Foot RT1 8.7531 N/A 7.4358 RT2 35.9464 N/A 22.0171 RT3 22.4696 N/A 9.0894 RT4 57.5439 N/A 6.4666 THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case Foot CT1 236.2042u N/A 207.8555u CT2 2.3885m N/A 1.5731m CT3 67.7502m N/A 9.7132m CT4 1.6059 N/A 336.8655m 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: 67788 Revision: 16-Mar-11 www.vishay.com 1 SQ1421EEH_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 10.9526 N/A 8.0863 RF2 35.4357 N/A 30.1499 RF3 21.7894 N/A 4.4914 RF4 56.2832 N/A 2.2801 THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case Foot CF1 231.5080u N/A 147.3530u CF2 2.0983m N/A 1.2441m CF3 57.6764m N/A 288.9102m CF4 1.5218 N/A 62.8004m Note N/A indicates not applicable www.vishay.com 2 Document Number: 67788 Revision: 16-Mar-11 SQ1421EEH_RC Vishay Siliconix Document Number: 67788 Revision: 16-Mar-11 www.vishay.com 3