LM2575D2T-005 Datasheet, PDF (24/28 Pages) ON Semiconductor – 1.0 A, Adjustable Output Voltage, Step-Down

LM2575, NCV2575
THE LM2575−ADJ STEP−DOWN VOLTAGE REGULATOR WITH 8.0 V @ 1.0 A OUTPUT POWER
CAPABILITY. TYPICAL APPLICATION WITH THROUGH−HOLE PC BOARD LAYOUT
Unregulated
DC Input
+V_in = +10 V to + 40 V
C1
100 mF
/50 V
4 Feedback
+V_in
LM2575−Adj
1
Output
2
3 GND 5 ON/OFF
L1
330 mH
D1
1N5819
C2
330 mF
/16 V
Regulated
Output Unfiltered
V_out1 = 8.0 V @1.0 A
L2
25 mH
Regulated
Output Filtered
V_out2 = 8.0 V @1.0 A
R2
10 k
C3
100 mF
/16 V
R1
1.8 k
ǒ Ǔ V_out + V_ref )
1
)
R2
R1
C1 − 100 mF, 50 V, Aluminium Electrolytic
C2 − 330 mF, 16 V, Aluminium Electrolytic
C3 − 100 mF, 16 V, Aluminium Electrolytic
V_ref = 1.23 V
R1 is between 1.0 k and 5.0 k
D1 − 1.0 A, 40 V, Schottky Rectifier, 1N5819
L1 − 330 mH, Tech 39: 77 458 BV, Toroid Core, Through−Hole, Pin 3 = Start, Pin 7 = Finish
L2 − 25 mH, TDK: SFT52501, Toroid Core, Through−Hole
R1 − 1.8 k
R2 − 10 k
Figure 38. Schematic Diagram of the 8.0 V @ 1.0 V Step−Down Converter Using the LM2575−Adj
(An additional LC filter is included to achieve low output ripple voltage)
GND_in
C1
L1
U1 LM2575
C2
D1
J1
GND_out
C3
L2 _+Vout2
+V_in
+V_out1
R2 R1
NOTE: Not to scale.
Figure 39. PC Board Component Side
NOTE: Not to scale.
Figure 40. PC Board Copper Side
References
• National Semiconductor LM2575 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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