LM317
P
D(max)
for T
A
= +50°C
70
60
50
40
R
θJA
30
0
5.0
10
15
20
L, LENGTH OF COPPER (mm)
Free Air
Mounted
Vertically
Minimum
Size Pad
3.0
2.0 oz. Copper
L
2.5
2.0
1.5
PD, MAXIMUM POWER DISSIPATION (W)
80
R
θ
JA, THERMAL RESISTANCE
JUNCTION TO AIR (
°
C/W)
3.5
L
Figure 19. D
2
PAK Thermal Resistance and Maximum
Power Dissipation versus P.C.B. Copper Length
D
6
*
1N4002
V
in
32 V to 40 V
V
in1
0.1
µF
Adjust 1
Current
Limit
Adjust
*
Diodes D
1
and D
2
and transistor Q
2
are added to
*
allow adjustment of output voltage to 0 V.
* D
6
protects both LM317's during an input short circuit.
1.0K
LM317
(1)
V
out1
R
SC
V
in2
LM317
(2)
V
out 2
240
D
1
1N4001
D
2
1N4001
5.0 k
Adjust 2
Voltage
Adjust
1N4001
D
3
D
4
-10 V
Q
2
2N5640
-10 V
IN4001
Output Range: 0
≤
V
O
≤
25 V
Output Range:
0
≤
I
O
≤
1.5 A
D
5
IN4001
+
10
µF
Q
1
2N3822
Figure 20. ‘‘Laboratory’’ Power Supply with Adjustable Current Limit and Output Voltage
http://onsemi.com
8
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
ÎÎÎÎ
25
1.0
30
I
out
V
out
+
1.0
µF
Tantalum
ONSEMI [ ON SEMICONDUCTOR ]
