Datasheet

INPUT CAPACITOR SELECTION
OUTPUT CAPACITOR SELECTION
TPS62220 , , TPS62221 , , TPS62222
TPS62223 , TPS62224 , TPS62225
TPS62227 , TPS62228 , TPS62229
www.ti.com ....................................................................................................................................... SLVS491E – SEPTEMBER 2003 – REVISED FEBRUARY 2009
Table 3. Inductor Selection
INDUCTOR VALUE COMPONENT SUPPLIER DIMENSIONS
4.7 µ H Sumida CDRH2D18/LD 4R7 3,2 mm × 3,2 mm × 2, 0 mm
4.7 µ H Murata LQH3C4R7M24 3,2 mm × 2,5 mm × 2, 0 mm
4.7 µ H Taiyo Yuden LBC2518 4R7 2,5 mm × 1,8 mm × 1,8 mm
4.7 µ H Sumida CMD4D11 4R7 4,4 mm × 5,8 mm × 1,2 mm
4.7 µ H Sumida CMD4D08 4R7 6,3 mm × 5,8 mm × 1, 0 mm
4.7 µ H Sumida CLSD09 4R7 4,9 mm × 4,9 mm × 1, 0 mm
4.7 µ H TDK VLF3010AT 4R7 2,8 mm × 2,6 mm × 1, 0 mm
6.8 µ H Sumida CDRH3D16 6R8 4,0 mm × 4,0 mm × 1,8 mm
6.8 µ H Sumida CMD4D11 4R7 4,0 mm × 5,8 mm × 1,2 mm
10 µ H Murata LQH4C100K04 4,5 mm × 3,2 mm × 2, 6 mm
10 µ H Sumida CDRH3D16 100 4,0 mm × 4,0 mm × 1,8 mm
10 µ H Sumida CLS4D14 100 4,9 mm × 4,9 mm × 1,5 mm
Because buck converters have a pulsating input current, a low ESR input capacitor is required. This results in the
best input voltage filtering, minimizing the interference with other circuits caused by high input voltage spikes.
Also, the input capacitor must be sufficiently large to stabilize the input voltage during heavy load transients. For
good input voltage filtering, usually a 4.7 µ F input capacitor is sufficient. It can be increased without any limit for
better input-voltage filtering. Ceramic capacitors show better performance because of the low ESR value, and
they are less sensitive against voltage transients and spikes compared to tantalum capacitors. Place the input
capacitor as close as possible to the input and GND pin of the device for best performance (see Table 4 for
capacitor selection).
The advanced fast response voltage mode control scheme of the TPS6222x allows the use of tiny ceramic
capacitors with a minimum value of 10 µ F without having large output voltage under and overshoots during
heavy load transients. Ceramic capacitors with low ESR values have the lowest output voltage ripple and are
recommended. If required, tantalum capacitors may be used as well (see Table 4 for capacitor selection). At
nominal load current, 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. The typical
output voltage ripple is 1% of the output voltage V
O
.
Table 4. Capacitor selection
CAPACITOR VALUE CASE SIZE COMPONENT SUPPLIER
4.7 µ F 0603 Contact TDK
4.7 µ F 0805 Taiyo Yuden JMK212BY475MG
Taiyo Yuden JMK212BJ106MG
10 µ F 0805
TDK C12012X5ROJ106K
0805 Contact TDK
22 µ F
1206 Taiyo Yuden JMK316BJ226
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Product Folder Link(s): TPS62220 TPS62221 TPS62222 TPS62223 TPS62224 TPS62225 TPS62227 TPS62228
TPS62229