MC7800, MC7800A, NCV7805
20
Vin − Vout , INPUT−OUTPUT VOLTAGE
DIFFERENTIAL (V)
16
PD , POWER DISSIPATION (W)
12
8.0
4.0
0
−50
q
HS
= 0°C/W
q
HS
= 5°C/W
q
HS
= 15°C/W
q
JC
= 5°C/W
q
JA
= 65°C/W
T
J(max)
= 150°C
2.5
I
O
= 1.0 A
2.0
1.5
1.0
0.5
I
O
= 500 mA
I
O
= 200 mA
I
O
= 20 mA
I
O
= 0 mA
No Heatsink
−25
0
25
50
75
100
125
150
DV
O
= 2% of V
O
− − −
Extended Curve for MC78XXB
−50
−25
0
25
50
75
100
125
0
−75
T
A
, AMBIENT TEMPERATURE (°C)
T
J
, JUNCTION TEMPERATURE (°C)
Figure 12. Worst Case Power Dissipation versus
Ambient Temperature (Case 221A)
Figure 13. Input Output Differential as a Function
of Junction Temperature (MC78XXC, AC, B)
JUNCTION-TO-AIR (
°
C/W)
70
60
50
Free Air
Mounted
Vertically
P
D(max)
for T
A
= 50°C
2.0 oz. Copper
L
3.0
2.5
2.0
1.5
Minimum
Size Pad
L
40
R
qJA
30
0
5.0
10
15
20
25
1.0
30
L, LENGTH OF COPPER (mm)
Figure 14. D
2
PAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
R
θ
JA, THERMAL RESISTANCE
JUNCTION−TO−AIR (
°
C/W)
90
80
70
60
50
Free Air
Mounted
Vertically
Minimum
Size Pad
P
D(max)
for T
A
= 50°C
2.0
2.0 oz. Copper
L
1.6
1.2
0.8
0.4
0
L
R
qJA
40
0
5.0
10
15
20
L, LENGTH OF COPPER (mm)
25
30
Figure 15. DPAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
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21
PD, MAXIMUM POWER DISSIPATION (W)
100
2.4
PD, MAXIMUM POWER DISSIPATION (W)
80
R
θ
JA, THERMAL RESISTANCE
3.5
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