SQ4937EY_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 7.9344 N/A 16.5723 RT2 27.8340 N/A 5.8542 RT3 24.8157 N/A 10.5182 RT4 49.4159 N/A 11.7903 THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case Foot CT1 408.5371u N/A 63.1322m CT2 7.6823m N/A 223.1259u CT3 110.3093m N/A 14.5653m CT4 1.6926 N/A 4.6830m 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: 63278 Revision: 20-May-11 www.vishay.com 1 This document is subject to change without notice. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 SQ4937EY_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 13.5605 N/A 6.0360 RF2 34.5635 N/A 15.9006 RF3 31.4724 N/A 5.2784 RF4 30.2314 N/A 17.3447 Junction to Ambient Case Foot CF1 758.8636u N/A 178.3756u THERMAL CAPACITANCE (Joules/°C) CF2 11.5535m N/A 2.9012m CF3 393.6521m N/A 706.2953u CF4 3.3255 N/A 41.3442m Note N/A indicates not applicable www.vishay.com 2 Document Number: 63278 Revision: 20-May-11 This document is subject to change without notice. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000 SQ4937EY_RC Vishay Siliconix Document Number: 63278 Revision: 20-May-11 www.vishay.com 3 This document is subject to change without notice. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000