Si7909DN_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 10.0659 1.7654 N/A RT2 56.5917 917.0038 m N/A RT3 16.2226 513.4962 m N/A RT4 11.1198 1.8041 N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CT1 567.6399 u 2.2536 m N/A N/A CT2 1.5867 381.7385 u CT3 11.1549 m 378.3022 m N/A CT4 265.4022 m 1.5575 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: 69270 Revision: 08-Aug-07 www.vishay.com 1 Si7909DN_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 12.7969 1.8167 N/A RF2 16.8918 2.6797 N/A RF3 13.9897 415.3083 m N/A RF4 50.3216 88.2917 m N/A Thermal Capacitance (Joules/°C) Junction to Ambient Case Foot CF1 624.3994 u 269.9786 u N/A CF2 15.4313 m 969.6215 u N/A CF3 335.4291 m 388.3320 m N/A CF4 1.4071 11.3066 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: 69270 Revision: 08-Aug-07 Si7909DN_RC Vishay Siliconix Document Number: 69270 Revision: 08-Aug-07 www.vishay.com 3