11

PROCEDURE (Adjustable Output Voltage Version)

EXAMPLE (Adjustable Output Voltage Version)

(especially the 100 kHz ESR) closely match the types

listed in the table. Refer to the capacitor

manufacturers data sheet for this information.

For output voltages greater than approximately 10V, an

additional capacitor is required. The compensation

capacitor is typically between 100 pF and 33 nF, and is

wired in parallel with the output voltage setting resistor,

R2. It provides additional stability for high output voltages,

low input-output voltages, and/or very low ESR output

capacitors, such as solid tantalum capacitors.

2

FF

R

10

31

1

C

×

×

=

This capacitor type can be ceramic, plastic, silver mica,

etc. (B ecause of the unstable characteristics of ceramic

capacitors made with Z5U material, they are not

recommended.)

The table shown in Figure 3 contains feed forward

capacitor values for various output voltages. In this

example, a 560 pF capacitor is needed.

LM2596 SERIES BUCK REGULATOR DESING PROCEDURE (ADJUSTABLE OUTPUT)

Through Hole Output Capacitor

Surface Mount Output Capacitor

Output

Voltage

(V)

Panasonic HFQ

Series

(

µF/V)

Nichicon PL

Series

(

µF/V)

Feedforward

capacitor

AVX TPS

Series

(

µF/V)

Sprague 595D

Series

(

µF/V)

Feedforward

Capacitor

2

820/35

820/35

33 nF

330/6.3

470/4

33 nF

4

560/35

470/35

10 nF

330/6.3

390/6.3

10 nF

6

470/25

470/25

3.3 nF

220/10

330/10

3.3 nF

9

330/25

330/25

1.5 nF

100/16

180/16

1.5 nF

12

330/25

330/25

1 nF

100/16

180/16

1 nF

15

220/35

220/35

680 pF

68/20

120/20

680 pF

24

220/35

150/35

560 pF

33/25

33/25

220 pF

28

100/50

100/50

390 pF

10/35

15/50

220 pF

Figure 3. Output Capacitor and Feedforward Capacitor Selection Table

LM2596 SERIES BUCK REGULATOR DESIGN PROCEDURE

Inductor Value Selection Guides (For Continuous Mode Operation)

Figure 4. LM2596-3.3

Figure 6. LM2596-12

3

L29

L21

L30

L31

L40

L22

L23

L32

L33

L34

L16

L15

L24

L25

68

H

µ

47

H

µ

33

H

µ

22

H

µ

15

H

µ

0.6

0.8 1.0

1.5

2.0 2.5 3.0

MAXIMUM LOAD CURRENT (A)

5V

6V

7V

8V

10V

15V

20V

40V

0.6

0.8 1.0

1.5

2.0 2.5 3.0

MAXIMUM LOAD CURRENT (A)

14V

16V

18V

19V

17V

25V

30V

40V

20V

15V

L27

L28

L36

L43

L37

L38

L30

L39

L40

L31

L32

L33

L34

L24

L23

L22

L21

L29

10

0

H

µ

15

0

H

µ

68

H

µ

47

H

µ

33

H

µ

22

H

µ

15

H

µ

LM2596 Simple switcher Power Converter 150kHz

3A Step-Down Voltage Regulator