LTC3851 LINER [Linear Technology], LTC3851 Datasheet - Page 5

• Manufacturer Part Number: LTC3851
• Description: Synchronous Step-Down Switching Regulator Controller
• Manufacturer: LINER [Linear Technology]

TYPICAL PERFORMANCE CHARACTERISTICS
AC COUPLED
0.2A TO 7.5A
100
100mV/DIV
90
80
70
95
85
75
5A/DIV
5A/DIV
4
Effi ciency and Power Loss vs
Input Voltage
Coincident Tracking with Master
Supply
V
V
FIGURE 11 CIRCUIT
I
V
LOAD
IN
OUT
OUT
8
= 12V
I
L
= 3.3V
Load Step
(Pulse-Skip Mode)
V
V
FIGURE 11 CIRCUIT
12
OUT
IN
EFFICIENCY,
= 12V
I
OUT
INPUT VOLTAGE (V)
= 1.5V
16
V
0.5V/DIV
MASTER
= 0.5A
10ms/DIV
20
24
100μs/DIV
POWER LOSS,
POWER LOSS,
28
I
2A LOAD
0.5V/DIV
OUT
I
EFFICIENCY,
OUT
V
I
OUT
OUT
32
= 5A
= 0.5A
= 5A
36
3851 G04
3851 G10
40
100
10000
1000
3851 G07
V
2A LOAD
0.5V/DIV
0.5V/DIV
MASTER
AC COUPLED
0.2A TO 7.5A
CONTINOUS
PULSE SKIP
V
OPERATION
100mV/DIV
Burst Mode
OUT
FORCED
5A/DIV
5A/DIV
5A/DIV
5A/DIV
5A/DIV
I
MODE
MODE
Ratiometric Tracking with Master
Supply
V
LOAD
OUT
I
L
Load Step
(Burst Mode Operation)
V
V
FIGURE 11 CIRCUIT
Inductor Current at Light Load
OUT
IN
V
V
I
FIGURE 11 CIRCUIT
LOAD
OUT
IN
= 12V
= 12V
= 1.5V
= 1.5V
= 1mA
10ms/DIV
100μs/DIV
1μs/DIV
3851 G11
3851 G05
3851 G08
AC COUPLED
0.2A TO 7.5A
100mV/DIV
0.5V/DIV
2V/DIV
5A/DIV
5A/DIV
3.0
2.5
2.0
1.5
1.0
0.5
V
I
V
LOAD
0
OUT
V
OUT
FB
4
Input DC Supply Current vs Input
Voltage
I
L
Start-Up with Prebiased Output
at 2V
Load Step
(Forced Continuous Mode)
V
V
FIGURE 11 CIRCUIT
8
OUT
IN
= 12V
= 1.5V
12
INPUT VOLTAGE (V)
16
20
20ms/DIV
LTC3851
100μs/DIV
24
28
0.5V/DIV
32
TK/SS
36
3851 G12
5
3851f
3851 G09
3851 G06
40