Analog Devices ADP1872-EVALZ, User Manual

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ADP1872-EVALZ/ADP1873-EVALZ User Guide UG-057
Rev. A | Page 9 of 20
CH1 2V
B
W
CH2 5A Ω
CH3 10V CH4 5V
M4ms A CH1 720mV
T 41.6%
1
2
3
4
OUTPUT VOLTAGE
INDUCTOR CURRENT
SW NODE
LOW SIDE
08548-
055
Figure 21. Power-Down Waveform During Heavy Load
CH1 50mV
B
W
CH2 5A Ω
CH3 10V
B
W
CH4 5V
M2µs A CH2 3.90A
T 35.8%
1
2
3
4
OUTPUT VOLTAGE
INDUCTOR CURRENT
SW NODE
LOW SIDE
08548-
056
Figure 22. Output Voltage Ripple Waveform During PSM Operation
at Light Load, 2 A
CH1 1V
B
W
CH2 5A Ω
CH3 10V
B
W
CH4 2V
M1ms A CH1 1.56V
T 63.2%
1
2
3
4
OUTPUT VOLTAGE
INDUCTOR CURRENT
SW NODE
LOW SIDE
08548-
057
Figure 23. Soft Start and RES Detect Waveform
2
CH2 5V
CH3 5V
MATH 2V 40ns CH4 2V
M40ns A CH2 4.20V
T 29.0%
3
M
4
HIGH SIDE
HS MINUS
SW
SW NODE
LOW SIDE
T
A
= 25°C
08548-
058
Figure 24. Output Drivers and SW Node Waveforms
2
CH2 5V
CH3 5V
MATH 2V 40ns CH4 2V
M40ns A CH2 4.20V
T 29.0%
3
M
4
HIGH SIDE
HS MINUS
SW
SW NODE
LOW SIDE 16ns (
t
f
, DRVL
)
25ns (
t
r
, DRVH
)
22ns (
t
pdh
, DRVH
)
T
A
= 25°C
08548-
059
Figure 25. Upper-Side Driver Rising and Lower-Side Falling Edge Waveforms,
C
IN
= 4.3 nF (Upper-/Lower-Side MOSFET),
Q
TOTAL
= 27 nC (V
GS
= 4.4 V (Q1), V
GS
= 5 V (Q3)
2
CH2 5V
CH3 5V
MATH 2V 20ns CH4 2V
M20ns A CH2 4.20V
T 39.2%
3
M
4
HIGH SIDE
HS MINUS
SW
SW NODE
LOW SIDE 18ns (
t
r
, DRVL
)
24ns (
t
pdh
, DRVL
)
11ns (
t
f
, DRVH
)
T
A
= 25°C
08548-
060
Figure 26. Upper-Side Driver Falling and Lower-Side Rising Edge Waveforms,
C
IN
= 4.3 nF (Upper-/Lower-Side MOSFET),
Q
TOTAL
= 27 nC (V
GS
= 4.4 V (Q1), V
GS
= 5 V (Q3)