MC7800_11 Datasheet, PDF (22/34 Pages) ON Semiconductor – 1.0 A Positive Voltage Regulators

MC7800, MC7800A, MC7800AE, NCV7800
20
q_JC = 5°C/W
16
q_HS = 0°C/W
q_JA = 65°C/W
T_J(max) = 150°C
12
q_HS = 5°C/W
8.0
q_HS = 15°C/W
4.0
No Heatsink
0
-50 -25
0 25 50 75 100 125 150
T_A, AMBIENT TEMPERATURE (°C)
Figure 13. Worst Case Power Dissipation versus
Ambient Temperature (Case 221A)
2.5
I_O = 1.0 A
I_O = 500 mA
2.0
I_O = 200 mA
1.5 I_O = 20 mA
1.0 ^{IO = 0 mA}
0.5
DV_O = 2% of V_O
- - - Extended Curve for MC78XXB
0
-75 -50 -25 0 25 50 75 100 125
T_J, JUNCTION TEMPERATURE (°C)
Figure 14. Input Output Differential as a Function
of Junction Temperature (MC78XXC, AC, B)
80
3.5
70
Free Air
P_D(max) for T_A = 50°C
3.0
Mounted
Vertically
60
50
Minimum
Size Pad
40
R_qJA
2.0 oz. Copper _2.5
L
ÎÎÎÎ_2.0
ÎÎÎÎ L
ÎÎÎÎÎÎÎÎ_1.5
30
1.0
0
5.0
10
15
20
25
30
L, LENGTH OF COPPER (mm)
Figure 15. D²PAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
100
Free Air
90
Mounted
Vertically
80
Minimum
70
Size Pad
60
2.4
P_D(max) for T_A = 50°C
2.0
2.0 oz. Copper
L
1.6
ÎÎÎÎÎÎÎÎ _L
1.2
ÎÎÎÎ_0.8
50
40
0
5.0
10
R_qJA
15
20
0.4
0
25
30
L, LENGTH OF COPPER (mm)
Figure 16. DPAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
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