Datasheet

( )
straightwire
4 L
L 0.2 L ln 0.75 nH
D
´
æ ö
» ´ ´ -
ç ÷
è ø
( )
NOM LOAD
SPIKE absolute
L
V V I
C
= + ´
TPS2590
www.ti.com SLUS960F –JULY 2009–REVISED MAY 2013
Where;
(23)
• V
NOM
equals the nominal supply voltage.
• I
LOAD
equals the load current.
• C equals the capacitance present at the input or output of the TPS2590.
• L equals the effective inductance seen looking into the source or the load.
The inductance due to a straight length of wire equals approximately.
Where;
(24)
• L equals the length of the wire.
• D equals wire diameter.
Some applications may require the addition of a TVS to prevent transients from exceeding the absolute ratings if
sufficient capacitance cannot be included.
Layout
Support Components
Locate all TPS2590 support components, R
RFLT
, R
RLIM
, C
CT
, or any input or output voltage clamps, close to their
connection pin. Connect the other end of the component to the inner layer GND without trace length. The traces
routing the R
RFLT
and R
RLIM
resistors to the TPS2590 should be as short as possible to reduce parasitic effects
on fault and current-limit accuracy.
PowerPad™
When properly mounted the PowerPad package provides significantly greater cooling ability than an ordinary
package. To operate at rated power the Power Pad must be soldered directly to the PC board GND plane
directly under the device. The PowerPad is at GND potential and can be connected using multiple vias to inner
layer GND. Other planes, such as the bottom side of the circuit board can be used to increase heat sinking in
higher current applications. Refer to Technical Briefs: PowerPAD™ Thermally Enhanced Package (TI Literature
Number SLMA002) and PowerPAD™ Made Easy (TI Literature Number SLMA004) for more information on using
this PowerPad package. These documents are available at www.ti.com (Search by Keyword).
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