ncv4275a ON Semiconductor, ncv4275a Datasheet - Page 12

• Manufacturer Part Number: ncv4275a
• Description: 5.0 V, 3.3 V 450 Ma Low-dropout Voltage Regulator With Reset
• Manufacturer: ON Semiconductor

Thermal Model
A discussion of thermal modeling is in the ON Semiconductor web site: http://www.onsemi.com/pub/collateral/BR1487−D.PDF.
NOTE:
Table 1. DPAK 5−Lead Thermal RC Network Models
Drain Copper Area (1 oz thick)
C_C10
R_R10
C_C1
C_C2
C_C3
C_C4
C_C5
C_C6
C_C7
C_C8
C_C9
R_R1
R_R2
R_R3
R_R4
R_R5
R_R6
R_R7
R_R8
R_R9
(SPICE Deck Format)
Bold face items represent the package without the external thermal system.
Junction
Junction
node1
node2
node3
node4
node1
node2
node3
node4
node5
node6
node7
node8
node9
node5
node6
node7
node8
node9
node1
node2
node3
node4
node5
node6
node7
node8
node9
Time constants are not simple RC products. Amplitudes
of mathematical solution are not the resistance values.
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Gnd
Figure 27. Non−Grounded Capacitor Thermal Ladder (“Foster” Ladder)
Each rung is exactly characterized by its RC−product
time constant; amplitudes are the resistances.
Figure 26. Grounded Capacitor Thermal Network (“Cauer” Ladder)
Junction
Junction
168 mm
1.00E−06
1.00E−05
6.00E−05
1.00E−04
4.36E−04
6.77E−02
1.51E−01
4.80E−01
168 mm
168 mm
2.97519
25.9805
46.5192
17.7808
10.322
8.2971
C
3.740
0.015
0.08
C
1
0.4
0.2
0.1
1
R
R
1
1
Cauer Network
2
2
2
C
C
2
R
R
2
2
2
http://onsemi.com
1.00E−06
1.00E−05
6.00E−05
1.00E−04
3.64E−04
1.92E−02
1.27E−01
736 mm
736 mm
736 mm
14.9320
19.2560
2.6171
1.6778
7.4246
0.1758
1.018
2.955
0.438
0.015
0.08
0.4
0.2
C
C
3
R
R
3
2
2
12
2
3
3
W−s/C
W−s/C
W−s/C
W−s/C
W−s/C
W−s/C
W−s/C
W−s/C
W−s/C
W−s/C
Units
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
(thermal ground)
(thermal ground)
3.79E+00
2.65E+01
8.71E+01
168 mm
1.36E−08
7.41E−07
1.04E−05
3.91E−05
1.80E−03
3.77E−01
Ambient
Ambient
0.0123
0.0585
0.0304
0.3997
12.851
35.471
46.741
3.571
3.115
Tau
R’s
C
C
Foster Network
n
n
2
R
R
n
n
1.361E−08
7.411E−07
1.029E−05
3.737E−05
1.376E−03
2.851E−02
9.475E−01
1.173E+01
8.59E+01
736 mm
0.0123
0.0585
0.0287
0.3772
28.94
2.68
1.38
5.92
7.39
Tau
R’s
2
Units
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
C/W
sec
sec
sec
sec
sec
sec
sec
sec
sec
sec