2

O

I

L

L

O

L(max)

O(max)

V

1

V

I

I = V

I

I

L

f

-

D

D

´

=

+

´

TPS62000, TPS62001, TPS62002, TPS62003

TPS62004, TPS62005, TPS62006, TPS62007, TPS62008

www.ti.com

SLVS294F – SEPTEMBER 2000 – REVISED AUGUST 2015

Typical Application (continued)

9.2.2 Detailed Design Procedure

9.2.2.1 Inductor Selection

A 10

μH minimum output inductor is used with the TPS6200x. Values larger than 22 μH or smaller than 10 μH

may cause stability problems because of the internal compensation of the regulator.

For output voltages greater than 1.8 V, a 22

μH inductance might be used in order to improve the efficiency of

the converter.

After choosing the inductor value of typically 10

μH, two additional inductor parameters should be considered:

first the current rating of the inductor and second the DC resistance.

The DC resistance of the inductance influences directly the efficiency of the converter. Therefore, an inductor

with lowest DC resistance should be selected for highest efficiency.

In order to avoid saturation of the inductor, the inductor should be rated at least for the maximum output current

plus the inductor ripple current which is calculated as:

Where:

•

ƒ = Switching frequency (750 kHz typical)

•

L = Inductor value

•

ΔIL = Peak-to-peak inductor ripple current

•

IL(max) = Maximum inductor current

(4)

The highest inductor current occurs at maximum VIN.

A more conservative approach is to select the inductor current rating just for the maximum switch current of the

TPS6200x which is 1.6 A with ILIM = VIN and 900 mA with ILIM = GND. See Table 1 for recommended inductors.

Table 1. Tested Inductors

OUTPUT CURRENT

INDUCTOR VALUE

COMPONENT SUPPLIER

COMMENTS

0 mA to 600 mA

10

μH

Coilcraft DO3316P-103

High efficiency

Coilcraft DT3316P-103

Sumida CDR63B-100

Sumida CDRH5D28-100

Coilcraft DO1608C-103

Smallest solution

Sumida CDRH4D28-100

0 mA to 300 mA

10

μH

Coilcraft DO1608C-103

High efficiency

Murata LQH4C100K04

Smallest solution

9.2.2.2 Output Capacitor Selection

For best performance, a low ESR output capacitor is needed. At output voltages greater than 1.8 V, ceramic

output capacitors can be used to show the best performance. Output voltages below 1.8 V require a larger output

capacitor and ESR value to improve the performance and stability of the converter.

Table 2. Capacitor Selection

OUTPUT VOLTAGE RANGE

OUTPUT CAPACITOR

OUTPUT CAPACITOR ESR

1.8 V

≤ VIN ≤ 5.5 V

Co ≥ 10 μF

ESR

≤ 120 mΩ

0.8 V

≤ VIN < 1.8 V

Co ≥ 47 μF

ESR > 50 m

Ω

Copyright © 2000–2015, Texas Instruments Incorporated

Submit Documentation Feedback

13

Product Folder Links: TPS62000 TPS62001 TPS62002 TPS62003 TPS62004 TPS62005 TPS62006 TPS62007

TPS62008