LT3508
APPLICATIONS INFORMATION
Output Tracking and Sequencing
Independent soft-start for each channel is shown in
Figure 8a. The output ramp time for each channel is set
by the soft-start capacitor as described in the soft-start
section.
Complexoutputtrackingandsequencingbetweenchannels
can be implemented using the LT3508’s TRACK/SS and
PG pins. Figure 8 shows several configurations for output
tracking and sequencing of 5V and 3.3V applications.
Independent Start-Up
Ratiometric Start-Up
Coincident Start-Up
V
V
V
V
V
OUT1
OUT1
OUT1
OUT2
V
OUT2
OUT2
1V/DIV
1V/DIV
1V/DIV
20ms/DIV
20ms/DIV
20ms/DIV
5V
5V
5V
TRACK/SS1 V
LT3508
TRACK/SS1 V
LT3508
TRACK/SS1 V
LT3508
OUT1
OUT1
OUT1
0.1ꢀF
0.22ꢀF
0.1ꢀF
3.3V
3.3V
3.3V
TRACK/SS2 V
TRACK/SS2 V
TRACK/SS2 V
OUT2
OUT2
OUT2
0.047ꢀF
R1
28.7k
R2
10.0k
(8a)
(8b)
(8c)
Output Sequencing
Controlled Power Up and Down
V
V
V
V
OUT1
OUT1
OUT2
OUT2
1V/DIV
1V/DIV
EXTERNAL SOURCE
20ms/DIV
20ms/DIV
5V
5V
TRACK/SS1 V
LT3508
TRACK/SS1 V
LT3508
OUT1
PG1
OUT2
OUT1
0.1ꢀF
EXTERNAL
SOURCE
+
–
3.3V
3.3V
TRACK/SS2 V
TRACK/SS2 V
OUT2
0.047ꢀF
R1
28.7k
R2
10.0k
(8d)
(8e)
Figure 8
3508fb
16
Linear [ Linear ]
