NCV4275

http://onsemi.com

7

Drain Copper Area (1 oz thick)

(SPICE Deck Format)

Cauer Network

Foster Network

Units

Tau

Tau

Units

C_C1

Junction

Gnd

1.00E−06

1.00E−06

W−s/C

1.361E−08

1.361E−08

sec

C_C2

node1

Gnd

1.00E−05

1.00E−05

W−s/C

7.411E−07

7.411E−07

sec

C_C3

node2

Gnd

6.00E−05

6.00E−05

W−s/C

1.005E−05

1.007E−05

sec

C_C4

node3

Gnd

1.00E−04

1.00E−04

W−s/C

3.460E−05

3.480E−05

sec

C_C5

node4

Gnd

2.82E−04

2.87E−04

W−s/C

7.868E−04

8.107E−04

sec

C_C6

node5

Gnd

5.58E−03

5.95E−03

W−s/C

7.431E−03

7.830E−03

sec

C_C7

node6

Gnd

4.25E−01

4.61E−01

W−s/C

2.786E+00

2.012E+00

sec

C_C8

node7

Gnd

9.22E−01

2.05

W−s/C

2.014E+01

2.601E+01

sec

C_C9

node8

Gnd

1.73

4.88

W−s/C

1.134E+02

1.218E+02

sec

C_C10

node9

Gnd

7.12

1.31

W−s/C

sec

R’s

R’s

R_R1

Junction

node1

0.015

0.0150

C/W

0.0123

0.0123

C/W

R_R2

node1

node2

0.08

0.0800

C/W

0.0585

0.0585

C/W

R_R3

node2

node3

0.4

0.4000

C/W

0.0257

0.0260

C/W

R_R4

node3

node4

0.2

0.2000

C/W

0.3413

0.3438

C/W

R_R5

node4

node5

1.85638

1.8839

C/W

1.77

1.81

C/W

R_R6

node5

node6

1.23672

1.2272

C/W

1.54

1.52

C/W

R_R7

node6

node7

9.81541

5.3383

C/W

4.13

3.46

C/W

R_R8

node7

node8

33.1868

18.9591

C/W

6.27

5.03

C/W

R_R9

node8

node9

27.0263

13.3369

C/W

60.80

29.30

C/W

R_R10

node9

gnd

1.13944

0.1191

C/W

C/W

NOTE:

Bold face items 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

Ri 1−e

−t taui