Datasheet

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     
SGLS243A − APRIL 2004 − REVISED JUNE 2008
15
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
APPLICATION INFORMATION
inductor selection (continued)
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:
DI
L
+ V
O
1–
V
O
V
I
L ƒ
I
L(max)
+ I
O(max)
)
DI
L
2
Where:
ƒ = Switching frequency (750 kHz typical)
L = Inductor value
∆I
L
= Peak-to-peak inductor ripple current
I
L(max)
= Maximum inductor current
The highest inductor current occurs at maximum V
I
.
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 = V
IN
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
Coilcraft DT3316P-103
Sumida CDR63B-100
Sumida CDRH5D28-100
High efficiency
Coilcraft DO1608C-103
Sumida CDRH4D28-100
Smallest solution
0 mA to 300 mA 10 µH
Coilcraft DS1608C-103 High efficiency
0 mA to 300 mA
10 µH
muRata LQH4C100K04 Smallest solution
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 ≤ V
I
≤ 5.5 V C
o
≥ 10 µF ESR ≤ 120 mΩ
0.8 V ≤ V
I
< 1.8 V C
o
≥ 47 µF ESR > 50 mΩ
See Table 3 for recommended capacitors.