Datasheet

R
SENSE
IN12
PASS
100
C
R>1k
out src
g
dV I
dt C
@
TPS2359
www.ti.com SLUS792H –FEBRUARY 2008–REVISED MAY 2013
12-V Inrush Slew Rate Control
As normally configured, the turn-on slew rate of the 12-V channel output voltage V
OUT12x
equals:
(7)
where I
SRC
equals the current sourced by the PASSx pin (nominally 30 μA) and C
g
equals the effective gate
capacitance. For purposes of this computation, one can assume that the effective gate capacitance
approximately equals the reverse transfer capacitance, C
RSS
. To reduce the slew rate, increase C
g
by connecting
additional capacitance from PASSx to ground. Place a resistor of at least 1000 Ω in series with the additional
capacitance to prevent it from interfering with the fast turn off of the FET. Since gate charge current is 30 µA and
the TPS2359 current limits at start up it is unlikely that this RC is required.
Figure 28. RC Slew Rate Control
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