Datasheet

LOADCURRENT
PATH
LOADCURRENT
PATH
(a) (b)
*ADDITIONAL DETAILSOMITTEDFORCLARITY.
SENSE
RESISTOR
TPS2458
R
SET
TPS2458
14
13
15
R
SET
14 1315
TPS2458
www.ti.com SLUS916B –FEBRUARY 2009–REVISED MAY 2010
Layout Considerations
TPS2458 applications require layout attention to ensure proper performance and minimize susceptibility to
transients and noise. In general, all runs should be as short as possible but the list below deserves first
consideration.
1. Decoupling capacitors on IN12 and IN3 should have minimal length to the pin and to GND.
2. SENM and SENP runs must be short and run side by side to maximize common mode rejection. Kelvin
connections should be used at the points of contact with R
SENSE
. (Figure 23).
3. SET runs need to be short on both sides of R
SET
.
4. These runs should be as short as possible and sized to carry at least 20 A, more if possible.
(a) Runs on both side of R
SENSE
.
(b) Runs from the drains and sources of the external FETs.
5. Runs from the BLK FETs to OUT12 should be as short as possible.
6. Runs connecting to IN3 and OUT3 should be sized for 1 A or more.
7. Connections to GND and SUM pins should be minimized after the runs above have been placed.
8. The device will dissipate low average power so soldering the powerpad to the board is not a requirement.
However, doing so will improve thermal performance and reduce susceptibility to noise.
Figure 23. Recommended R
SENSE
Layout
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