Si7844DP_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 55.1947 1.3251 N/A RT2 11.1866 1.7811 N/A RT3 13.1709 949.5000 m N/A RT4 5.4478 1.4443 N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CT1 1.4037 632.5614 u N/A CT2 21.2313 m 2.1004 m N/A CT3 284.3546 m 817.4728 m N/A CT4 1.0248 m 13.4950 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: 69248 Revision: 27-Jul-07 www.vishay.com 1 Si7844DP_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 6.7017 1.7943 N/A RF2 13.1135 2.0703 N/A RF3 16.5834 823.2986 m N/A RF4 48.6014 812.1014 m N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 1.1322 m 417.8669 u N/A CF2 22.6418 m 1.6506 m N/A CF3 284.4815 m 31.7564 m N/A CF4 1.2592 926.1856 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: 69248 Revision: 27-Jul-07 Si7844DP_RC Vishay Siliconix Document Number: 69248 Revision: 27-Jul-07 www.vishay.com 3