
LM2576
http://onsemi.com
23
THE LM2576ADJ STEPDOWN VOLTAGE REGULATOR WITH 8.0 V @ 1.0 A OUTPUT POWER
CAPABILITY. TYPICAL APPLICATION WITH THROUGHHOLE 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 k
W, 0.25 W
R2
10 k
W, 0.25 W
Figure 38. Schematic Diagram of the 8.0 V @ 3.0 A StepDown Converter Using the LM2576ADJ
Vref = 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
Vout2 = 8.0 V @ 3.0 A
Unregulated
DC Input
C2
1000
mF
/16 V
C1
100
mF
/50 V
LM2576ADJ
1
5
3ON/OFF
GN
D
+Vin
+Vin = 10 V to 40 V
4
Feedback
Vout + Vref ) 1.0 )
R2
R1
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
Vout
GNDout
GNDin
+Vin
00059_00
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