SQJ461EP_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 3.0336 23.4722 m Foot N/A RT2 9.3314 688.2031 m N/A RT3 6.2693 1.8758 N/A RT4 51.8152 911.2786 m N/A Junction to Ambient Case CT1 12.0631 m 1.3636 m N/A CT2 304.0603 m 1.2578 m N/A CT3 73.5835 m 9.8360 m N/A CT4 1.2863 8.1431 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: 66568 Revision: 05-Mar-10 www.vishay.com 1 SQJ461EP_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 5.4827 12.6762 u N/A RF2 9.9545 1.1822 N/A RF3 17.5487 1.2928 N/A RF4 37.4972 1.0216 N/A THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case Foot CF1 10.1325 m 379.2088 u N/A CF2 73.9415 m 564.0357 u N/A CF3 480.6324 m 5.0549 m N/A CF4 1.2577 869.8118 u N/A Note N/A indicates not applicable www.vishay.com 2 Document Number: 66568 Revision: 05-Mar-10 SQJ461EP_RC Vishay Siliconix Document Number: 66568 Revision: 05-Mar-10 www.vishay.com 3