LM2576
http://onsemi.com
23
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
C1 − 100 mF, 50 V, Aluminium Electrolytic
C2 − 1000 mF, 16 V, Aluminium Electrolytic
D1 − 3.0 A, 40 V, Schottky Rectifier, 1N5822
L1 − 150 mH, RL2444, Renco Electronics
R1 − 1.8 kW, 0.25 W
R2 − 10 kW, 0.25 W
Figure 38. Schematic Diagram of the 8.0 V @ 3.0 A Step−Down Converter Using the LM2576−ADJ
V
ref
= 1.23 V
R1 is between 1.0 k and 5.0 k
D1
1N5822
L1
150 mH
Output
2
R2
10 k
R1
1.8 k
Regulated
Output Filtered
V
out2
= 8.0 V @ 3.0 A
Unregulated
DC Input
C2
1000 mF
/16 V
C1
100 mF
/50 V
LM2576−ADJ
1
53ON/OFFGN
D
+V
in
+V
in
= 10 V to 40 V
4 Feedback
V
out
+ V
ref
)
ǒ
1.0 )
R2
R1
Ǔ
ON/OFF
Figure 39. Printed Circuit Board Layout
Component Side
Figure 40. Printed Circuit Board Layout
Copper Side
LM2576
U1
D1 R1
R2
C1
+
C2
+
L1
ON/OFF
V
out
GND
out
GND
in
+V
in
00059_00
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
