Si3851DV_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 Mosfet Ambient Schottky Case Foot Mosfet Foot Schottky RT1 41.3839 50.5349 N/A 29.1228 29.3755 RT2 17.8424 18.1012 N/A 22.7539 22.6128 RT3 45.3883 46.3955 N/A 25.6195 32.7248 RT4 45.3854 49.9684 N/A 12.5038 10.2869 Thermal Capacitance (Joules/°C) Junction to Ambient Mosfet Ambient Schottky Case Foot Mosfet Foot Schottky CT1 16.2326 m 11.8607 m N/A 4.1372 m 2.9802 m CT2 382.1978 u 309.9804 u N/A 1.7457 m 1.4990 m CT3 2.2476 m 1.9009 m N/A 15.3997 m 13.5018 m CT4 1.8854 1.7071 N/A 255.9679 u 216.5573 u 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: 74669 Revision: 03-May-07 www.vishay.com 1 Si3851DV_RC Vishay Siliconix R-C THERMAL MODEL FOR FILTER CONFIGURATION R-C VALUES FOR FILTER CONFIGURATION Thermal Resistance (°C/W) Junction to Ambient Mosfet Ambient Schottky Case Foot Mosfet Foot Schottky RF1 22.8768 24.5444 N/A 19.6121 19.9249 RF2 52.3054 54.6038 N/A 49.1762 50.8226 RF3 29.9906 36.8954 N/A 10.9809 12.0196 RF4 44.8272 48.9564 N/A 10.2308 12.2329 Thermal Capacitance (Joules/°C) Junction to Ambient Mosfet Ambient Schottky Case Foot Mosfet Foot Schottky CF1 297.9236 u 270.1590 u N/A 217.3897 u 208.7151 u CF2 1.7173 m 1.4336 m N/A 1.2357 m 1.1098 m CF3 18.6657 m 13.7160 m N/A 13.1791 m 13.5935 m CF4 1.8697 1.7442 N/A 3.6092 m 7.4595 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: 74669 Revision: 03-May-07 Si3851DV_RC Vishay Siliconix Document Number: 74669 Revision: 03-May-07 www.vishay.com 3 Si3851DV_RC Vishay Siliconix www.vishay.com 4 Document Number: 74669 Revision: 03-May-07