Datasheet

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Up
Dn
Sense
V =12V
I
ASIC
VCORE
VCCI O
I 2
O
PTH12010L
1
10
4
5
62
3
9
Tra ck
GND
Inhibit
7
Vadj
Sense
+
V 1=3.3V
O
V 2=1.8V
O
R1
2kW
R5
10k0
R4
100kW
R3
11k0
R1
130 W
C2
330 Fm
C4
330 Fm
C6
0.68 Fm
C5
0.1 Fm
C3
330 Fm
C1
330 Fm
+
+
PTH12020W
7
10
4
5
62
3
9
Tra ck
V
I
V
I
V
O
V
O
GND
Inhibit
1
Adjust
+
TL7702B
V
CC
GND
SENSE
RESIN
REF
CT
RESET
RESET
8
7
2
1
3
5
6
4
+
8
8
PTH12050W/L
SLTS214H – MAY 2003 – REVISED OCTOBER 2007
Figure 17. Application Circuit Demonstrating Prebias Startup
Notes:
1. Output prebias holdoff is an inherent feature to all PTH120x0L and PTV120x0W/L modules. It has now been
incorporated into all modules (including W-suffix modules with part numbers of the form PTH120x0W), with a
production lot date code of 0423 or later.
2. The prebias start-up feature is not compatible with Auto-Track. If the rise in the output is limited by the
voltage applied to the Track control pin, the output sinks current during the period that the track control
voltage is below that of the back-feeding source. For this reason, it is recommended that Auto-Track be
disabled when not being used. This is accomplished by connecting the Track pin to the input voltage, V
I
. This
raises the Track pin voltage well above the set-point voltage prior to the module ’ s start up, thereby, defeating
the Auto-Track feature.
3. To further ensure that the regulator's output does not sink current when power is first applied (even with a
ground signal applied to the Inhibit control pin), the input voltage must always be greater than the applied
prebias source. This condition must exist throughout the power-up sequence of the power system.
18 Submit Documentation Feedback Copyright © 2003 – 2007, Texas Instruments Incorporated
Product Folder Link(s): PTH12050W/L