Functional Characteristics
Startup Waveforms
4
Functional Characteristics
The following applies unless otherwise noted: TA = 25°C, RSVIN = 10Ω, CSVIN = 0.1 µF, CPVIN
10 µF, L = 4.7 µH, COUT (BUCK) = 10 µF, PFET = FDC642P, COUT (LDO) = 10 µF.
=
4.1
Startup Waveforms
NOTE: There is a delay (3.5 ms typ.) before the output voltage turns on.
Figure 14: Startup Using the
Shutdown Pin
Figure 15: Turn Off Using the
Shutdown Pin
V
2V/DIV
V
2V/DIV
LDO
LDO
V
BUCK
V
500 mV/DIV
2V/DIV
500 mV/DIV
2V/DIV
BUCK
V
V
SHDN
SHDN
1.0 ms/DIV
1.0 ms/DIV
V
V
V
= 5.0V
I
t
= No Load
V
= 5.0V
I
= No Load
LOAD
IN
LOAD
IN
= 3.3V
~ 3.5 ms
V
V
= 3.3V
LDO
BUCK
DLY
LDO
BUCK
= 1.2V
= 1.2V
Figure 16: Enable Threshold at V
3.5V
=
Figure 17: Enable Threshold at V
= 5.0V
IN
IN
2V/DIV
1V/DIV
2V/DIV
1V/DIV
V
V
LDO
LDO
V
V
BUCK
SHDN
BUCK
SHDN
V
V
1V/DIV
1V/DIV
100 ms/DIV
100 ms/DIV
V
= 5.0V
I
= 10 mA
V
V
V
= 5.0V
I
= 10 mA
LOAD
IN
LOAD
IN
V
V
= 3.3V
V
= 0.96V (Note)
= 3.3V
V
= 1.12V (Note)
TH
LDO
BUCK
TH
LDO
BUCK
= 1.2V
= 1.2V
Copyright © 2008 Marvell
April 14, 2008, 2.00
Doc. No. MV-S102809-00 Rev. G
Page 33
Document Classification: Proprietary
MARVELL [ MARVELL TECHNOLOGY GROUP LTD. ]
