Si7421DN_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 and Cauer/Filter configurations are included. 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) Foot Junction to Ambient Case RT1 49.1065 714.0639 m N/A RT2 17.0470 762.7202 m N/A RT3 8.7341 711.3159 m N/A RT4 6.1124 1.6119 N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CT1 1.5218 558.9606 u N/A CT2 27.5314 m 6.1452 m N/A CT3 748.7952 m 28.6777 m N/A CT4 4.2555 m 9.1652 m N/A 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: 69214 Revision: 23-Jul-07 www.vishay.com 1 Si7421DN_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 8.8174 1.2789 N/A RF2 17.4872 1.0615 N/A RF3 21.8233 921.3068 m N/A RF4 32.8721 538.2932 m N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 3.9175 m 592.1328 u N/A CF2 28.3429 m 4.6001 m N/A CF3 690.8084 m 402.9641 u N/A CF4 1.4062 8.3522 m N/A 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: 69214 Revision: 23-Jul-07 Si7421DN_RC Vishay Siliconix Document Number: 69214 Revision: 23-Jul-07 www.vishay.com 3