SiR870DP_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 RT1 13.2078 113.0557m Foot N/A RT2 6.0649 373.8497m N/A RT3 2.7995 542.5297m N/A RT4 31.9278 168.8730m N/A THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case Foot CT1 1.0638 932.3844u N/A CT2 125.2382m 185.9394m N/A CT3 26.0917m 17.2344m N/A CT4 3.3100 664.3159m 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: 67639 Revision: 17-Feb-11 www.vishay.com 1 SiR870DP_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 5.9102 148.7450m N/A RF2 9.2682 433.2167m N/A RF3 26.8208 202.0592m N/A RF4 11.7265 409.8945m N/A THERMAL CAPACITANCE (Joules/°C) Junction to Ambient Case CF1 23.6931m 1.1231m Foot N/A CF2 233.8261m 13.5351m N/A CF3 1.1772 18.7512m N/A CF4 9.6436 122.9028m N/A Note N/A indicates not applicable www.vishay.com 2 Document Number: 67639 Revision: 17-Feb-11 SiR870DP_RC Vishay Siliconix Document Number: 67639 Revision: 17-Feb-11 www.vishay.com 3