LM2574, NCV2574
http://onsemi.com
23
The LM2574−ADJ Step−Down Voltage Regulator with 5.0 V @ 0.5 A Output Power Capability Typical
Application With Through−Hole PC Board Layout
D1
1N5819
L1
330 mH
Output
7
1
Feedback
R2
6.12 kW
R1
2.0 kW
L2
22 mH
Regulated
Output Filtered
V
out
= 5.0 V @ 0.5 A
Output
Ripple Filter
Unregulated
DC Input
C2
220 mF
C3
100 mF
C1
22 mF
LM2574−ADJ
5
34ON
/OFFPwr
Gnd
+V
in
2 Sig
Gnd
+V
in
= 7.0 to 40 V
Gnd Gnd
C1 − 22 mF, 63 V, Aluminium Electrolytic
C2 − 220 mF, 16 V, Aluminium Electrolytic
C3 − 100 mF, 16 V Aluminium Electrolytic
D1 − 1.0 A, 40 V, Schottky Rectifier, 1N5819
L1 − 330 mH, RL−1284−330, Renco Electronics
L2 − 25 mH, SFT52501, TDK
R1 − 2.0 kW, 0.1%, 0.25 W
R2 − 6.12 kW, 0.1%, 0.25 W
Figure 39. Schematic Diagram of the 5.0 V @ 0.5 A Step−Down Converter Using the LM2574−ADJ
(An additional LC filter is included to achieve low output ripple voltage)
(12)
(5)
(3)
(14)
(6)
(4)
LM2574
C1
C2
+
+
U1
L1
D1
V
out
Gnd
+V
in
C3
+
Gnd
L2
R1 R2
Figure 40. PC Board Layout Component Side
NOTE: Not to scale.
Figure 41. PC Board Layout Copper Side
NOTE: Not to scale.
References
• Marty Brown “Practical Switching Power Supply Design”, Academic Press, Inc., San Diego 1990
• Ray Ridley “High Frequency Magnetics Design”, Ridley Engineering, Inc. 1995
