Si4684DY_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. These techniques are described in "A Simple Method of Generating Thermal Models for a Power MOSFET"[1]. When implemented in P-Spice, these values have matching characteristic curves to the Single Pulse Transient Thermal Impedance curves for the MOSFET. R-C values for the electrical circuit in the Foster/Tank configuration are included. The corresponding values for the Cauer/Filter configuration are available upon request. Note: For a detailed explanation of implementing these values in P-SPICE, refer to Application Note AN609 Thermal Simulations Of Power MOSFETs on 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 2.7730 RT1 5.4825 N/A RT2 14.0940 N/A 5.6035 RT3 11.8997 N/A 12.5420 RT4 18.5795 N/A 6.9783 Junction to Ambient Case Foot CT1 8.6182 m N/A 617.0550 µ CT2 93.6547 m N/A 18.1606 m CT3 6.1489 N/A 73.2626 m CT4 3.2294 N/A 9.1092 m Thermal Capacitance (Joules/°C) 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:74111 Revision 14-Nov-05 www.vishay.com 1 Si4684DY_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 4.0154 N/A 3.2171 RF2 9.4382 N/A 13.5708 RF3 8.0801 N/A 4.3045 RF4 28.4203 N/A 6.7275 Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 5.4161 m N/A 475.8931 µ CF2 37.1706 m N/A 5.3294 m CF3 176.0921 m N/A 65.4259 m CF4 1.9925 N/A 2.3240 m Note: NA indicates not applicable Reference: [1] "A Simple Method of Generating Thermal Models for a Power MOSFET" by Wharton McDaniel and Kandarp Pandya, IEEE / SEMITHERM 2002 www.vishay.com 2 Document Number:74111 Revision 14-Nov-05 Si4684DY_RC Vishay Siliconix Document Number:74111 Revision 14-Nov-05 www.vishay.com 3