Application Notes

For technical support or further information, visit http://power.ti.com

Table 2-1: Suggested Input/Output Capacitors

N/R –Not recommended. The ripple current rating and ESR does not meet the requirements.

Capacitor Recommendations for

the PT6510 Series of

Integrated Switching Regulators

Input Capacitors:

The recommended input capacitance is determined by

330 µF minimum value (300 µF for Oscon or low-ESR

tantalum types), and 1 A minimum ripple current rating.

Ripple current and less than 100 m

Ω equivalent series

resistance (ESR) are the major parameters, along with

temperature, when selecting an input capacitor. Tanta-

lum capacitors have a recommended minimum voltage

rating of twice 2

× (max. DC voltage + AC ripple). This

is standard practice to insure reliability.

Output Capacitors:

The ESR of the required output capacitor must not be

greater than 150 m

Ω. Electrolytic capacitors have poor

ripple performance at frequencies greater than 400 kHz

but excellent low-frequency transient response. Above

the ripple frequency, ceramic capacitors are necessary to

improve the transient response and reduce any high

frequency noise components apparent during higher

current excursions. Preferred low-ESR type capacitor

part numbers are identified in Table 2-1.

Tantalum Capacitors

Tantalum type capacitors may be used for the output but

only the AVX TPS, Sprague 593D/594/595, or Kemet

T495/T510 series. These capacitors are recommended

over many other tantalum types due to their higher rated

surge, power dissipation, and ripple current capability.

As a caution the TAJ series by AVX is not recommended.

This series has considerably higher ESR, reduced power

dissipation, and lower ripple current capability. The TAJ

series is less reliable than the AVX TPS series when

determining power dissipation capability. Tantalum or

Oscon types are recommended for applications where

ambient temperatures fall below 0 °C.

Capacitor Table

Table 2-1 identifies the characteristics of capacitors from

a number of vendors with acceptable ESR and ripple

current (rms) ratings. The number of capacitors required

at both the input and output buses is identified for each

capacitor type.

This is not an extensive capacitor list. Capacitors from other

vendors are available with comparable specifications. Those listed

are for guidance. The RMS ripple current rating and ESR

(at 100 kHz) are critical parameters necessary to insure both

optimum regulator performance and long capacitor life.

r

o

t

i

c

a

p

a

C

/

r

o

d

n

e

V

t

n

e

n

o

p

m

o

C

s

e

i

r

e

S

s

c

i

t

s

i

r

e

t

c

a

r

a

h

C

r

o

t

i

c

a

p

a

Cy

t

i

t

n

a

u

Q

g

n

i

k

r

o

W

e

g

a

t

l

o

V)

F

µ

(

e

u

l

a

V

R

S

E

.

x

a

M

z

H

k

0

0

1

t

a

e

l

p

p

i

R

.

x

a

M

C

°

5

8

t

a

t

n

e

r

r

u

C

)

s

m

r

I

(

e

z

i

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l

a

c

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P

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m

m

(

t

u

p

n

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s

u

B

t

u

p

t

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s

u

B

r

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b

m

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c

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V

5

2

V

5

3

V

5

3

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µ

0

6

5

F

µ

0

9

3

F

µ

0

3

3

5

6

0

0

.

0

Ω

5

6

0

.

0

Ω

7

1

1

.

0

Ω

A

m

5

0

2

1

A

m

5

0

2

1

A

m

5

5

5

5

1

x

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2

1

5

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x

5

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2

1

5

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1

1

x

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1

2

R

/

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1

1

1

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1

6

5

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1

C

F

U

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1

9

3

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3

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1

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5

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1

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µ

0

3

3

F

µ

0

7

4

F

µ

0

3

3

F

µ

0

5

1

0

2

1

.

0

Ω

2

5

0

.

0

Ω

5

2

0

.

0

Ω

0

3

0

.

0

÷2 Ω

A

m

5

5

5

A

m

0

2

2

1

A

m

0

0

5

3

A

m

0

0

2

3

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1

x

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0

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x

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1

5

.

0

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x

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1

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.

0

1

x

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R

/

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1

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2

L

L

2

1

X

8

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1

3

3

B

V

6

1

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X

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L

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0

2

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0

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1

7

4

B

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5

3

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3

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M

P

/

L

P

V

5

3

V

5

3

V

0

5

0

6

5F

µ

0

3

3F

µ

0

7

4F

µ

8

4

0

.

0

Ω

5

6

0

.

0

÷2 Ω

6

4

0

.

0

Ω

A

m

0

6

3

1

A

m

0

2

0

1

A

m

0

7

4

1

5

1

x

6

1

5

1

x

5

.

2

1

5

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x

8

1

1

1

1

1

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H

H

M

1

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5

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1

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P

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6

H

H

M

1

3

3

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1

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6

H

H

M

1

1

7

4

H

1

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c

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a

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C

F

)

g

t

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c

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f

r

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(

V

0

1

V

5

3

V

6

1

0

0

0

1F

µ

0

3

3F

µ

0

3

3F

µ

3

4

0

.

0

Ω

5

6

0

.

0

Ω

0

5

1

.

0

Ω

A

m

5

0

2

1

A

m

5

0

2

1

A

m

0

7

6

5

.

6

1

x

2

1

6

1

x

5

.

2

1

2

.

0

1

x

0

1

1

1

R

/

N

1

1

1

Q

L

2

0

1

A

1

C

F

V

E

E

Q

L

1

3

3

V

1

C

F

V

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E

P

1

3

3

C

1

C

F

V

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E

S

S

-

n

o

c

s

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V

S

V

0

1

V

0

1

V

0

2

0

3

3F

µ

F

µ

0

3

3

0

5

1F

µ

5

2

0

.

0

Ω

5

2

0

.

0

Ω

4

2

0

.

0

÷2 Ω

A

m

0

0

5

3

>

A

m

0

0

8

3

>

A

m

0

0

6

3

5

.

0

1

x

0

.

0

1

3

.

0

1

x

3

.

0

1

3

.

0

1

x

3

.

0

1

1

1

2

1

1

2

M

0

3

3

S

S

0

1

M

0

3

3

V

S

0

1

M

0

5

1

V

S

0

2

t

n

u

o

M

e

c

a

f

r

u

S

=

V

S

X

V

A

m

u

l

a

t

n

a

T

S

P

T

V

0

1

V

0

1

V

0

1

F

µ

0

3

3

F

µ

0

3

3

F

µ

0

2

2

0

0

1

.

0

÷2 Ω

0

0

1

.

0

÷2 Ω

5

9

0

.

0

Ω

A

m

0

0

5

2

>

A

m

0

0

0

3

>

A

m

0

0

0

2

>

x

L

3

.

7

x

W

3

.

4

H

1

.

4

2

2

2

1

1

2

0

0

1

0

R

0

1

0

M

7

3

3

V

S

P

T

0

6

0

0

R

0

1

0

M

7

3

3

V

S

P

T

0

0

1

0

R

5

0

1

0

M

7

2

2

V

S

P

T

t

e

m

e

K

/

0

1

5

T

5

9

4

T

V

0

1

V

0

1

F

µ

0

3

3

F

µ

0

2

2

3

3

0

.

0

Ω

7

0

.

0

÷

Ω

5

3

0

.

0

=

2

Ω

A

m

0

0

4

1

A

m

0

0

0

2

>

W

7

.

5

x

L

3

.

7

H

0

.

4

x

2

2

1

2

S

A

0

1

0

M

7

3

3

X

0

1

5

T

S

A

0

1

0

M

7

2

2

X

5

9

4

T

e

u

g

a

r

p

S

D

4

9

5

V

0

1

V

0

1

F

µ

0

3

3

F

µ

0

2

2

5

4

0

.

0

Ω

5

6

0

.

0

Ω

A

m

0

5

3

2

A

m

0

0

0

2

>

x

L

3

.

7

x

W

0

.

6

H

1

.

4

2

2

1

2

T

2

R

0

1

0

0

X

7

3

3

D

4

T

2

D

0

1

0

0

X

7

2

2

D

4

9

5

PT6510 Series