Datasheet

LTC3851A
5
3851afa
Typical perForMance characTerisTics
Load Step
(Burst Mode Operation)
Load Step
(Forced Continuous Mode)
Load Step
(Pulse-Skipping Mode)
Inductor Current at Light Load
Start-Up with Prebiased Output
at 2V
Coincident Tracking with Master
Supply
Efficiency and Power Loss
vs Input Voltage
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
3851A 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
3851A 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
3851A G07
FORCED
CONTINOUS
MODE
5A/DIV
PULSE-SKIPPING
MODE
5A/DIV
Burst Mode
OPERATION
5A/DIV
1µs/DIVV
OUT
= 1.5V
V
IN
= 12V
I
LOAD
= 1mA
FIGURE 11 CIRCUIT
3851A G08
V
OUT
2V/DIV
V
FB
0.5V/DIV
20ms/DIV
3851A G09
TK/SS
0.5V/DIV
10ms/DIV
3851A G10
V
OUT
2A LOAD
0.5V/DIV
V
MASTER
0.5V/DIV
INPUT VOLTAGE (V)
4
70
EFFICIENCY (%)
POWER LOSS (mW)
75
85
90
95
12
20
24 32
3851A G04
80
8 16
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