Vishay Siliconix
Si4856ADY_RC
Document Number:74114
Revision 14-Nov-05
www.vishay.com
1
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
configuration are included. The corresponding values
for the Cauer/Filter configuration are available upon
request.
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
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.
R-C VALUES FOR TANK CONFIGURATION
Thermal Resistance (C/W)
Junction to
Ambient
Case
Foot
RT1
2.0053
N/A
468.2017 m
RT2
20.8011
N/A
4.8276
RT3
28.2729
N/A
7.4177
RT4
28.8060
N/A
5.9020
Thermal Capacitance (Joules/C)
Junction to
Ambient
Case
Foot
CT1
1.6405 m
N/A
2.0074 m
CT2
24.4894 m
N/A
39.9180 m
CT3
358.8053 m
N/A
189.7165 m
CT4
2.5583
N/A
11.7115 m
www.vishay.com
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Document Number:74114
Revision 14-Nov-05
Vishay Siliconix
Si4856ADY_RC
R-C THERMAL MODEL FOR FILTER CONFIGURATION
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
R-C VALUES FOR FILTER CONFIGURATION
Thermal Resistance (C/W)
Junction to
Ambient
Case
Foot
RF1
1.3054
N/A
3.1425
RF2
24.3531
N/A
8.7149
RF3
34.9946
N/A
3.5588
RF4
19.2364
N/A
3.1301
Thermal Capacitance (Joules/C)
Junction to
Ambient
Case
Foot
CF1
263.0147
N/A
4.8377 m
CF2
19.8868 m
N/A
7.2041 m
CF3
325.1676 m
N/A
168.4432 m
CF4
3.6944
N/A
17.9200 m
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