NCV8184
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Table 3. DPAK 5−LEAD THERMAL RC NETWORK MODELS*
Drain Copper Area (1 oz thick) 100 mm
2
645 mm
2
100 mm
2
645 mm
2
(SPICE Deck Format) Cauer Network Foster Network
100 mm
2
645 mm
2
Units Tau Tau Units
C_C1 Junction Gnd 0.0000016 0.0000016 W−s/C 1.00E-06 1.00E-06 sec
C_C2 node1 Gnd 0.0000060 0.0000060 W−s/C 1.00E-05 1.00E-05 sec
C_C3 node2 Gnd 0.0000177 0.0000177 W−s/C 1.00E-04 1.00E-04 sec
C_C4 node3 Gnd 0.0001586 0.0001587 W−s/C 1.76E-04 1.76E-04 sec
C_C5 node4 Gnd 0.0001927 0.0001931 W−s/C 0.0010 0.0010 sec
C_C6 node5 Gnd 0.0056684 0.0058019 W−s/C 0.030 0.030 sec
C_C7 node6 Gnd 0.0832719 0.1225791 W−s/C 0.285 0.299 sec
C_C8 node7 Gnd 0.1125429 0.3555671 W−s/C 3.00 3.00 sec
C_C9 node8 Gnd 0.5161495 1.2959188 W−s/C 9.03 11.80 sec
C_C10 node9 Gnd 1.4600223 1.8396650 W−s/C 55.2 79.0 sec
100 mm
2
645 mm
2
R’s R’s
R_R1 Junction node1 0.8287213 0.8287120 °C/W 0.490938 0.490938 °C/W
R_R2 node1 node2 1.9304163 1.9303119 °C/W 1.061544 1.061544 °C/W
R_R3 node2 node3 4.7751915 4.7743247 °C/W 3.356895 3.356895 °C/W
R_R4 node3 node4 2.3736457 2.3705112 °C/W 1.606314 1.606314 °C/W
R_R5 node4 node5 2.0679537 2.0623650 °C/W 5.00 5.00 °C/W
R_R6 node5 node6 5.3364094 5.1102633 °C/W 5.00 5.00 °C/W
R_R7 node6 node7 6.0331860 3.2428679 °C/W 2.00 2.00 °C/W
R_R8 node7 node8 22.7616126 8.6995800 °C/W 9.147005 5.071663 °C/W
R_R9 node8 node9 17.9894079 16.1165074 °C/W 17.23178 3.646957 °C/W
R_R10 node9 gnd 22.7199543 16.7871407 °C/W 41.92202 34.68827 °C/W
*Bold face items in the tables above represent the package without the external thermal system.
The Cauer networks generally have physical significance
and may be divided between nodes to separate thermal
behavior due to one portion of the network from another.
The Foster networks, though when sorted by time constant
(as above) bear a rough correlation with the Cauer networks,
are really only convenient mathematical models. Cauer
networks can be easily implemented using circuit simulating
tools, whereas Foster networks may be more easily
implemented using mathematical tools (for instance, in a
spreadsheet program), according to the following formula:
R(t) +
n
S
i + 1
R
i
ǒ
1−e
−tń tau
i
Ǔ
