Si7940DP_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 5.3180 980.2053 m N/A RT2 9.3111 597.8482 m N/A RT3 12.8194 1.9208 N/A RT4 57.1957 1.9129 N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CT1 1.5367 m 2.7568 m N/A CT2 19.0942 m 780.1691 m N/A CT3 178.4249 m 8.4382 m N/A CT4 1.2235 685.3641 u 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: 73747 Revision 17-Jan-06 www.vishay.com 1 Si7940DP_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 7.0242 2.3340 N/A RF2 12.3677 1.1677 N/A RF3 14.8863 1.4412 N/A RF4 50.6164 524.0947 m N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 1.3728 m 462.9568 u N/A CF2 23.5350 m 1.5125 m N/A CF3 242.2420 m 8.4132 m N/A CF4 1.1481 1.8305 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: 73747 Revision 17-Jan-06 Si7940DP_RC Vishay Siliconix Document Number: 73747 Revision 17-Jan-06 www.vishay.com 3