TPS64200,TPS64201

TPS64202,TPS64203

SLVS485 − AUGUST 2003

www.ti.com

13

For a first approximation use:

L = 10

µH

Selecting the Inductor Value

The main parameters when choosing the inductor are current rating and inductance. The inductance mainly

determines the inductor current ripple. The TPS6420x operates with a wide range of inductor values. Values

between 4.7

µH and 47 µH work in most applications. Select an inductor with a current rating exceeding the

TPS64200. The device can either work with minimum-on-time or minimum-off-time, depending on input voltage

and output voltage.

The device works with minimum-on-time if:

V

I *

V

O *

I

O

r

DS(on) *

R

RL

xI

O w

t

off

,min

V

O )

V

SCHOTTKY )

R

RL

I

O

ton,min

(8)

with

L

+ V

Dt

DI

For minimum-on-time:

L

+

V

I

–V

O

–I

O

r

DS(on)

–R

RL

I

O

ton,min

DI

with:

(9)

For minimum-off-time:

L

+

V

O )

V

SCHOTTKY )

R

RL

I

O

t

off

,min

DI

(10)

Table 1. List of Inductors Tested With the TPS6420x

MANUFACTURER

TYPE

INDUCTANCE

DC RESISTANCE

SATURATION CURRENT

TDK

SLF7032T−100M1R4

10

µH ±20%

53 m

Ω ±20%

1.4 A

TDK

SLF6025−150MR88

15

µH ±20%

85 m

Ω ±20%

0.88 A

Sumida

CDRH6D28−5R0

5

µH

23 m

Ω

2.4 A

Sumida

CDRH103R−100

10

µH

45 m

Ω

2.4 A

Sumida

CDRH4D28−100

10

µH

95 m

Ω

1.0 A

Sumida

CDRH5D18−6R2

6.2

µH

71 m

Ω

1.4 A

Coilcraft

DO3316P−472

4.7

µH

18 m

Ω

5.4 A

Coilcraft

DT3316P−153

15

µH

60 m

Ω

1.8 A

Coilcraft

DT3316P−223

22

µH

84 m

Ω

1.5 A

Wurth

744 052 006

6.2

µH

80 m

Ω

1.45 A

Wurth

74451115

15

µH

90 m

Ω

0.8 A