Datasheet

LTC3868-1
5
38681fd
TYPICAL PERFORMANCE CHARACTERISTICS
Effi ciency and Power Loss
vs Output Current
Effi ciency vs Load Current
Load Step (Burst Mode Operation)
Load Step
(Forced Continuous Mode)
Load Step (Pulse-Skipping Mode)
Inductor Current at Light Load
Soft Start-Up
Effi ciency vs Input Voltage
OUTPUT CURRENT (A)
0.0001
40
EFFICIENCY (%)
50
60
70
80
0.001 0.01 0.1 1 10
38681 G02
30
20
10
0
90
100
V
IN
= 5V
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
90
92
94
38681 G03
88
86
84
80
10
20
5
15
25 28
82
98
96
FIGURE 12 CIRCUIT
V
OUT
= 3.3V
I
OUT
= 4A
OUTPUT CURRENT (A)
0.0001
40
EFFICIENCY (%)
POWER LOSS (mW)
50
60
70
80
0.001 0.01 0.1 1 10
38681 G01
30
20
10
0
90
100
10
100
1000
1
0.1
10000
FIGURE 12 CIRCUIT
V
IN
= 12V
V
OUT
= 3.3V
Burst Mode
OPERATION
PULSE-
SKIPPING
FCM
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
20µs/DIV
38681 G04
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
20µs/DIV
38681 G05
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
20µs/DIV
38681 G06
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
Burst Mode
OPERATION
2A/DIV
FORCED
CONTINUOUS
MODE
PULSE-
SKIPPING
MODE
2µs/DIV
38681 G07
V
OUT
= 3.3V
I
LOAD
= 200µA
FIGURE 12 CIRCUIT
V
OUT2
2V/DIV
V
OUT1
2V/DIV
20ms/DIV
38681 G08
FIGURE 12 CIRCUIT