LM2576
THE LM2576–ADJ STEP–DOWN VOLTAGE REGULATOR WITH 8.0 V @ 1.0 A OUTPUT POWER
CAPABILITY. TYPICAL APPLICATION WITH THROUGH–HOLE PC BOARD LAYOUT
Figure 38. Schematic Diagram of the 8.0 V @ 3.0 A Step–Down Converter Using the LM2576–ADJ
4
Feedback
Unregulated
DC Input
+V
in
L1
150
LM2576–ADJ
Regulated
Output Filtered
µ
H
1
+V = 10 V to 40 V
in
Output
2
V
= 8.0 V @ 3.0 A
out2
R2
10 k
3
Gnd
5
ON/OFF
C1
100 µF
/50 V
C2
1000
/16 V
D1
1N5822
µF
R1
1.8 k
ON/OFF
R2
R1
V
V
1.0
out
= 1.23 V
ref
V
ref
R1 is between 1.0 k and 5.0 k
C1
C2
D1
L1
R1
R2
–
–
–
–
–
–
100 µF, 50 V, Aluminium Electrolytic
1000 µF, 16 V, Aluminium Electrolytic
3.0 A, 40 V, Schottky Rectifier, 1N5822
150 µH, RL2444, Renco Electronics
1.8 kΩ, 0.25 W
10 kΩ, 0.25 W
Figure 39. Printed Circuit Board Layout
Component Side
Figure 40. Printed Circuit Board Layout
Copper Side
LM2576
U1
D1
R1
R2
ON/OFF
C1
+
+
C2
V
out
+V
in
L1
Gnd
in
Gnd
out
NOTE: Not to scale.
NOTE: Not to scale.
References
• National Semiconductor LM2576 Data Sheet and Application Note
• National Semiconductor LM2595 Data Sheet and Application Note
• Marty Brown “Practical Switching Power Supply Design”, Academic Press, Inc., San Diego 1990
• Ray Ridley “High Frequency Magnetics Design”, Ridley Engineering, Inc. 1995
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