Si4858DY_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) Junction to Ambient Case Foot RT1 34.4210 N/A 4.7331 RT2 5.4870 N/A 1.4307 RT3 18.8020 N/A 1.5757 RT4 21.2900 N/A 8.2605 Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CT1 1.2814 N/A 24.9402 m CT2 20.9559 m N/A 23.1289 m CT3 75.0816 m N/A 3.5274 CT4 11.3428 N/A 150.3408 m 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: 74631 Revision: 14-May-07 www.vishay.com 1 Si4858DY_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 7.7368 N/A 2.5741 RF2 18.1600 N/A 4.3623 RF3 37.3247 N/A 6.6949 RF4 16.7785 N/A 2.3687 Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 15.0827 m N/A 10.0830 m CF2 53.1334 m N/A 6.7685 m CF3 1.0478 N/A 111.9353 m CF4 9.5469 N/A 834.1374 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: 74631 Revision: 14-May-07 Si4858DY_RC Vishay Siliconix Document Number: 74631 Revision: 14-May-07 www.vishay.com 3