LM2574, NCV2574

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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 k

W

R1

2.0 k

W

L2

22

mH

Regulated

Output Filtered

Output

Ripple Filter

Unregulated

DC Input

C2

220

mF

C3

100

mF

C1

22

mF

LM2574−ADJ

5

3

4ON/OFF

Pwr

Gnd

2

Sig

Gnd

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 k

W, 0.1%, 0.25 W

R2

−

6.12 k

W, 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

Gnd

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