SiR640DP_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. R-C values for the electrical circuit in the Foster/tank and Cauer/filter configurations are included. When implemented in P-SPICE, these values have matching characteristic curves to the single-pulse transient thermal impedance curves for the MOSFET. These RC values can be used in the P-SPICE simulation to evaluate the thermal behavior of the MOSFET junction temperature under a defined power profile. These techniques are described in application note AN609, “Thermal Simulation of Power MOSFETs on the P-SPICE Platform”. R-C THERMAL MODEL FOR TANK CONFIGURATION T (Junction) RT1 RT2 RT3 RT4 CT1 CT2 CT3 CT4 T (Ambient) R-C VALUES FOR TANK CONFIGURATION THERMAL RESISTANCE (°C/W) Junction to Ambient Case Foot RT1 14.0538 434.7239m N/A RT2 30.1790 326.6422m N/A RT3 2.4819 313.3708m N/A RT4 6.8507 119.2806m N/A THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case CT1 1.2687 188.0847m Foot N/A CT2 3.4427 80.0757m N/A CT3 30.9763m 19.2764m N/A CT4 108.6318m 215.3963u N/A Note N/A indicates not applicable This document is intended as a SPICE modeling guideline and does not constitute a commercial product datasheet. Designers should refer to the appropriate datasheet of the same number for guaranteed specification limits. Document Number: 67446 Revision: 11-Jan-11 www.vishay.com 1 SiR640DP_RC Vishay Siliconix R-C THERMAL MODEL FOR FILTER CONFIGURATION T (Junction) RF2 RF1 CF1 CF2 RF3 RF4 T (Ambient) CF4 CF3 GND R-C VALUES FOR FILTER CONFIGURATION THERMAL RESISTANCE (°C/W) Junction to Ambient Case Foot RF1 3.8432 136.0251m N/A RF2 8.2834 621.7276m N/A RF3 29.1817 256.9326m N/A RF4 12.8148 183.3722m N/A THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case CF1 21.0565m 1.0362m Foot N/A CF2 95.9188m 14.5286m N/A CF3 1.1092 139.2882m N/A CF4 11.0065 37.5437m N/A Note N/A indicates not applicable www.vishay.com 2 Document Number: 67446 Revision: 11-Jan-11 SiR640DP_RC Vishay Siliconix Document Number: 67446 Revision: 11-Jan-11 www.vishay.com 3