Datasheet

LTC3853
5
3853fa
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs Output Current
and Mode
Efficiency and Power Loss
vs Input Voltage
Efficiency vs Output Current
and Mode
Load Step
(Burst Mode Operation)
Load Step
(Forced Continuous Mode)
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
POWER LOSS (mW)
75
80
85
15
25
3853 G03
70
65
60
5 10 20
90
95
100
1.0
0.8
1.2
1.4
0.4
0.6
0.2
0
1.6
1.8
2.0
30
V
OUT
= 3.3V
I
OUT
= 2A
FIGURE 15 MODIFIED
WITH DCR SENSING
EFFICIENCY
POWER LOSS
40µs/DIV
V
OUT
100mV/DIV
AC COUPLED
I
L
2A/DIV
I
LOAD
2A/DIV
3853 G04
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 0A TO 3A
FIGURE 15 CIRCUIT
40µs/DIV
V
OUT
100mV/DIV
AC COUPLED
I
L
2A/DIV
I
LOAD
2A/DIV
3853 G05
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 0A TO 3A
FIGURE 15 CIRCUIT
Inductor Current at Light Load
Load Step
(Pulse Skip Mode)
40µs/DIV
V
OUT
100mV/DIV
AC COUPLED
I
L
2A/DIV
I
LOAD
2A/DIV
3853 G06
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 0A TO 3A
FIGURE 15 CIRCUIT
1µs/DIV
Burst Mode
OPERATION
2A/DIV
FORCED
CONTINUOUS
MODE
2A/DIV
PULSE SKIPPING
MODE
2A/DIV
3853 G07
V
IN
= 12
V
OUT
= 1.8V
I
LOAD
= 100mA
FIGURE 15 CIRCUIT
LOAD CURRENT (A)
0.01 0.1 1 10
40
EFFICIENCY (%)
50
60
70
80
30
20
10
0
90
100
3853 G01
BURST
DCM
CCM
V
IN
= 12V
V
OUT
= 1.8V
FIGURE 15 MODIFIED
WITH DCR SENSING
LOAD CURRENT (A)
0.01 0.1 1 10
40
EFFICIENCY (%)
50
60
70
80
30
20
10
0
90
100
3853 G02
BURST
DCM
CCM
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 15 MODIFIED
WITH DCR SENSING