6

TEST CIRCUIT AND LAYOUT GUIDELINES

Careful layout is important with any switching regulator. Rapidly switching currents associated with wiring

inductance generate voltage transients, which can cause problems. To minimize inductance and ground loops,

the lengths of the leads indicated by heavy lines in Figure 1 below should be kept as short as possible. Single-

point grounding (as indicated in Figure 1) or ground plane construction should be used for best results. When

using the Adjustable version, place the programming resistors as close as possible to

sensitive feedback wiring short.

V

IN

Unregulated

DC Input

+V

IN

1

+

C

IN

GND 3

5

2

Output

4

Feedback

L1

D1

MBR360

C

OUT

V

OUT

FIXED OUTPUT

+

ON/OFF

L

O

A

D

Figure 1(a). Fixed Output Voltage Versions

C - 100 µF, 75V, Aluminum Electrolytic

IN

C

- 330 µF, 25V, Aluminum Electrolytic

OUT

D1 - Schottky, MBR360

L1 - 330 µH,

R1 - 2k, 0.1%

R2 - 6.12k, 0.1%

3L Electronic Corp. TC-331M-1.0A- 5026

330 µH

330 µF

100 µF

LM2575, to keep the

LM2575

LM2575 1.0A Step - Down Voltage Switching Regulators