MVPG15x/MVPG16
Datasheet
4.2
Switching Waveforms
NOTE: For repeatability of measuring output ripple (V
) for the BUCK regulator, the standard test
BUCK (P-P)
procedure limits the scope bandwidth to 20 MHz and uses a coax cable with very short leads
terminated into 50Ω. The coax leads must be routed away from the switching node as much as
possible.
Figure 23: Switching Waveforms—
Figure 24: Switching Waveforms—
DCM Mode
PWM Mode
V
SW
5V/DIV
V
5V/DIV
SW
I
IND
200 mA/DIV
5 mV/DIV
100 mV/DIV
V
10 mV/DIV
BUCK
V
BUCK
I
IND
V
500 mV/DIV
IN
500 ns/DIV
1.0 µs/DIV
V
V
= 5.0V
V
= 200 mV
= 231 mA
= 1.1A
V
= 5.0V
I
= 248 mA
IN
IN(P-P)
IND(P-P)
IND(PK)
IN
IND(PK)
= 1.2V
= 1.0A
I
I
V
= 1.2V
Freq = 313 kHz
BUCK
BUCK
I
I
= 50 mA
OUT
OUT
V
= 4.9 mV (Note)
Freq = 910 kHz
V
= 13 mV (Note)
OUT(P-P)
OUT(P-P)
Figure 25: PWM Output Ripple
Voltage
Figure 26: Switching Waveforms—
DCM Mode-Zoom
V
5V/DIV
SW
V
10 mV/DIV
10 mV/DIV
200 mA/DIV
BUCK
V
BUCK
I
IND
100 ms/DIV
500 ns/DIV
V
V
= 5.0V
I
= 1.0A
V
= 5.0V
I
= 24 mA
OUT
IN
OUT
IN
= 1.2V
V
= 8.6 mV (Note)
V
= 1.2V
BUCK
Ringing Freq = 6.0 MHz
BUCK
OUT(P-P)
Doc. No. MV-S102809-00 Rev. G
Page 36
Copyright © 2008 Marvell
April 14, 2008, 2.00
Document Classification: Proprietary
MARVELL [ MARVELL TECHNOLOGY GROUP LTD. ]
