Datasheet
2
O
I L
L O L(max) O(max)
V
1
V I
I = V I I
L f
-
D
D ´ = +
´
(4)
OUTPUT CAPACITOR SELECTION
1
2 3
O
O
I
RMS(C ) O
V
1
V
I = V
L f
-
´ ´
´
´
(5)
O
I
O O
O
V
1
V
1
V = V ESR
L 8 Cf f
-
æ ö
D ´ ´ +
ç ÷
´ ´ ´
è ø
(6)
TPS62000, TPS62001, TPS62003
TPS62004, TPS62005, TPS62006
TPS62007, TPS62008
SLVS294E – SEPTEMBER 2000 – REVISED AUGUST 2008 ...........................................................................................................................................
www.ti.com
Where:
ƒ = Switching frequency (750 kHz typical)
L = Inductor value
Δ 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 µ H 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 µ H Coilcraft DO1608C-103 High efficiency
Murata LQH4C100K04 Smallest solution
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 µ F ESR ≤ 120 m Ω
0.8 V ≤ V
I
< 1.8 V C
o
≥ 47 µ F ESR > 50 m Ω
See Table 3 for recommended capacitors.
If an output capacitor is selected with an ESR value ≤ 120 m Ω , its RMS ripple current rating always meets the
application requirements. Just for completeness, the RMS ripple current is calculated as:
The overall output ripple voltage is the sum of the voltage spike caused by the output capacitor ESR plus the
voltage ripple caused by charge and discharging the output capacitor:
Where the highest output voltage ripple occurs at the highest input voltage V
I
.
14 Submit Documentation Feedback Copyright © 2000 – 2008, Texas Instruments Incorporated
Product Folder Link(s): TPS62000, TPS62001, TPS62003 TPS62004, TPS62005, TPS62006 TPS62007, TPS62008