Datasheet

SS /TR
TPS54260
EN
PWRGD
SS /TR
EN
PWRGD
EN1
PWRGD1
VOUT1
VOUT2
EN1,EN2
VOUT1
VOUT2
EN
TPS54160
3
SS/TR
4
PWRGD
6
EN
TPS54160
3
SS/TR4
PWRGD
6
TPS54260
TPS54260
TPS54260
www.ti.com SLVSA86A –MARCH 2010–REVISED DECEMBER 2010
DETAILED DESCRIPTION (continued)
Figure 30. Schematic for Sequential Start-Up Figure 31. Sequential Startup using EN and
Sequence PWRGD
Figure 32. Schematic for Ratiometric Start-Up Figure 33. Ratio-Metric Startup using Coupled
Sequence SS/TR pins
Figure 32 shows a method for ratio-metric start up sequence by connecting the SS/TR pins together. The
regulator outputs will ramp up and reach regulation at the same time. When calculating the slow start time the
pull up current source must be doubled in Equation 6. Figure 33 shows the results of Figure 32.
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