Datasheet
Notes on Use of Auto-Track™
U2
PTH04T260W
Vi
Auto Track
GND VoAdj
Vo
TurboTrans
+Sense
−Sense
Inhibit/
UVLO
U3
TPS3808G50
6
GND
2
4
3
MR
CT
SENSE
5
1
U1
PTH05T210W
Vi
Auto Track
GND VoAdj
Vo
TurboTrans
+Sense
−Sense
+
Inhibit/
UVLO
SmartSync
+
R
TT
V
O1
= 3.3 V
C
O1
V
O2
= 1.8 V
C
O2
R
TT
R
SET2
4.75 kΩ
R
SET1
1.62 kΩ
C
I2
C
I1
RESET
V
I
= 5 V
C
4
0.1 µF
C
3
4700 µF
UDG−06042
PTH04T260W , PTH04T261W
www.ti.com
.................................................................................................................................................. SLTS273E – SEPTEMBER 2006 – REVISED JULY 2009
1. The Track pin voltage must be allowed to rise above the module set-point voltage before the module
regulates at its adjusted set-point voltage.
2. The Auto-Track function tracks almost any voltage ramp during power up, and is compatible with ramp
speeds of up to 1 V/ms.
3. The absolute maximum voltage that may be applied to the Track pin is the input voltage V
I
.
4. The module cannot follow a voltage at its track control input until it has completed its soft-start initialization.
This takes about 20 ms from the time that a valid voltage has been applied to its input. During this period, it
is recommended that the Track pin be held at ground potential.
5. The Auto-Track function is disabled by connecting the Track pin to the input voltage (V
I
). When Auto-Track is
disabled, the output voltage rises at a quicker and more linear rate after input power has been applied.
Figure 24. Sequenced Power Up and Power Down Using Auto-Track
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