TEST CIRCUIT AND LAYOUT GUIDELINES

Figure 1. Standard Test Circuits and Layout Guides

As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductance can generate

voltage transients which can cause problems. For minimal inductance and ground loops, the wires indicated by heavy lines should

be wide printed circuit traces and

should be kept as short as possible. For best results, external components should be located as close to the switcher lC as possible

using ground plane construction or single point grounding.

If open core inductors are used, special care must be taken as to the location and positioning of this type of inductor. Allowing

When using the adjustable version, special care must be taken as to the location of the feedback resistors and the associated wiring.

Physically locate both resistors near the IC, and route the wiring away from the inductor, especially an open core type of inductor.

+

L1

C

OUT

+

C

IN

2

3

4

5

+V

IN

+

L1

+

Fixed Output Voltage Versions

C

- 470 F,50V,Aluminum Electrolytic Nichicon “PL Series”

IN

µ

C

- 220 F,25V,Aluminum Electrolytic Nichicon “ PL Series”

D1 - 5A,40V Schottky Rectifer,1N5825

L1 - 68 H,L38

OUT

µ

µ

+

L1

C

OUT

+

C

IN

2

3

4

5

+V

IN

+

R1

R2

C

FF

Adjustable Output Voltage Versions

Select R1 to be approximately 1

C

- 470 F,50V,Aluminum Electrolytic Nichicon “PL Series”

IN

µ

k,use a1% resistor for best stability.

C

- 220 F,35V,Aluminum Electrolytic Nichicon “ PL Series”

D1 - 5A,40V Schottky Rectifer,1N5825

L1 - 68 H,L38

R1 - 1k ,1%

C

- see Application Information Section

Ω

µ

µ

Ω

OUT

FF

V=V (1+

)

OUT

REF

R = R (

-1)

21

where V = 1.23V

REF

V

V

OUT

REF

R

R

2

1

7

BEIJING ESTEK ELECTRONICS CO.,LTD

LM2596

3AStep-Down VoltageRegulator