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INDUCTOR SELECTION

DIL +

V

O

V

I

V

I *

V

O

L

ƒsw

DIL(MAX) + IO(MAX) )

DIL

2

(4)

OUTPUT CAPACITOR SELECTION

DVO +

V

O

V

I

V

I *

V

O

L

ƒsw

1

8

C

O

ƒsw )

ESR

, maximum for high V

I

(5)

TPS62300, TPS62301, TPS62302

TPS62303, TPS62304, TPS62305,

TPS62311, TPS62313, TPS62315, TPS62320, TPS62321

SLVS528E – JULY 2004 – REVISED NOVEMBER 2007

Even though the inductor does not influence the operating frequency, the inductor value has a direct effect on the

ripple current. The selected inductor has to be rated for its dc resistance and saturation current. The inductor

ripple current (

L = inductor value

Normally, it is advisable to operate with a ripple of less than 30% of the average output current. Accepting larger

values of ripple current allows the use of low inductances, but results in higher output voltage ripple, greater core

losses, and lower output current capability.

frequency-dependent components:

• The losses in the core material (magnetic hysteresis loss, especially at high switching frequencies)

• Additional losses in the conductor from the skin effect (current displacement at high frequencies)

• Magnetic field losses of the neighboring windings (proximity effect)

• Radiation losses

The following inductor series from different suppliers have been used with the TPS6230x, TPS6231x, and

TPS6232x converters.

Table 2. List of Inductors

MANUFACTURER

SERIES

DIMENSIONS

FDK

MIPW3226

MIPSA2520

Murata

LQM2HP

LQ CB2016

Taiyo Yuden

LQ CB2012

LQ CBL2012

TDK

VLF3010AT

Coilcraft

LPS3010

JFE

32R1560

The advanced fast-response voltage mode control scheme of the TPS6230x, TPS6231x, and TPS6232x allows

the use of tiny ceramic capacitors. Ceramic capacitors with low ESR values have the lowest output voltage ripple

and are recommended. The output capacitor requires either an X7R or X5R dielectric. Y5V and Z5U dielectric

capacitors, aside from their wide variation in capacitance over temperature, become resistive at high frequencies.

At nominal load current, the device operates in PWM mode and the overall output voltage ripple is the sum of the

voltage spike caused by the output capacitor ESR plus the voltage ripple caused by charging and discharging the

output capacitor:

At light loads, the device operates in power-save mode and the output voltage ripple is independent of the output

capacitor value. The output voltage ripple is set by the internal comparator thresholds and propagation delays.

Copyright © 2004–2007, Texas Instruments Incorporated

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Product Folder Link(s): TPS62300, TPS62301, TPS62302 TPS62303, TPS62304, TPS62305, TPS62311, TPS62313,

TPS62315, TPS62320, TPS62321