Datasheet

LTC3851-1
5
38511fa
TYPICAL PERFORMANCE CHARACTERISTICS
Load Step
(Burst Mode Operation)
Load Step
(Forced Continuous Mode)
Load Step
(Pulse skip Mode)
Inductor Current at Light Load
Start-Up with Prebiased Output
at 2V
Coincident Tracking with Master
Supply
Ratiometric Tracking with Master
Supply
Input DC Supply Current
vs Input Voltage
Effi ciency and Power Loss
vs Input Voltage
INPUT VOLTAGE (V)
4
70
EFFICIENCY (%)
POWER LOSS (mW)
75
85
90
95
12
20
24 32
38511 G04
80
816
28
100
100
1000
10000
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 11 CIRCUIT
POWER LOSS,
I
OUT
= 5A
POWER LOSS,
I
OUT
= 0.5A
EFFICIENCY,
I
OUT
= 0.5A
EFFICIENCY,
I
OUT
= 5A
I
LOAD
5A/DIV
0.2A TO 7.5A
V
OUT
100mV/DIV
AC-COUPLED
I
L
5A/DIV
100µs/DIVV
OUT
= 1.5V
V
IN
= 12V
FIGURE 11 CIRCUIT
38511 G05
I
LOAD
5A/DIV
0.2A TO 7.5A
V
OUT
100mV/DIV
AC-COUPLED
I
L
5A/DIV
100µs/DIVV
OUT
= 1.5V
V
IN
= 12V
FIGURE 11 CIRCUIT
38511 G06
I
LOAD
5A/DIV
0.2A TO 7.5A
V
OUT
100mV/DIV
AC-COUPLED
I
L
5A/DIV
100µs/DIVV
OUT
= 1.5V
V
IN
= 12V
FIGURE 11 CIRCUIT
3851 G07
FORCED
CONTINOUS
MODE
5A/DIV
PULSE SKIP
MODE
5A/DIV
Burst Mode
OPERATION
5A/DIV
1µs/DIVV
OUT
= 1.5V
V
IN
= 12V
I
LOAD
= 1mA
FIGURE 11 CIRCUIT
38511 G08
V
OUT
2V/DIV
V
FB
0.5V/DIV
20ms/DIV
38511 G09
TK/SS
0.5V/DIV
10ms/DIV
38511 G10
V
MASTER
0.5V/DIV
V
OUT
2A LOAD
0.5V/DIV
V
MASTER
0.5V/DIV
V
OUT
2A LOAD
0.5V/DIV
10ms/DIV
38511 G11
INPUT VOLTAGE (V)
4
SUPPLY CURRENT (mA)
12
20
24 40
38511 G12
816
28
32
36
3.0
2.5
2.0
1.5
1.0
0.5
0