LTC3851A_15 Datasheet, PDF (5/30 Pages) Linear Technology – Synchronous Step-Down Switching Regulator Controller

Typical Performance Characteristics
LTC3851A
Efficiency and Power Loss
vs Input Voltage
100
EFFICIENCY,
95
I_OUT = 5A
90
POWER LOSS,
I_OUT = 5A
10000
85
80
75
70
4
EFFICIENCY,
I_OUT = 0.5A
1000
POWER LOSS,
I_OUT = 0.5A
8 12 16
V_IN = 12V
V_OUT = 3.3V
FIGURE 11 CIRCUIT
100
20 24 28 32
INPUT VOLTAGE (V)
3851A G04
Load Step
(Forced Continuous Mode)
I_LOAD
5A/DIV
0.2A TO 7.5A
I_L
5A/DIV
V_OUT
100mV/DIV
AC-COUPLED
V_OUT = 1.5V
100µs/DIV
V_IN = 12V
FIGURE 11 CIRCUIT
3851A G06
Load Step
(Burst Mode Operation)
I_LOAD
5A/DIV
0.2A TO 7.5A
I_L
5A/DIV
V_OUT
100mV/DIV
AC-COUPLED
V_OUT = 1.5V
100µs/DIV
V_IN = 12V
FIGURE 11 CIRCUIT
3851A G05
Load Step
(Pulse-Skipping Mode)
I_LOAD
5A/DIV
0.2A TO 7.5A
I_L
5A/DIV
V_OUT
100mV/DIV
AC-COUPLED
V_OUT = 1.5V
100µs/DIV
V_IN = 12V
FIGURE 11 CIRCUIT
3851A G07
Inductor Current at Light Load
FORCED
CONTINOUS
MODE
5A/DIV
Burst Mode
OPERATION
5A/DIV
PULSE-SKIPPING
MODE
5A/DIV
V_OUT = 1.5V
1µs/DIV
V_IN = 12V
I_LOAD = 1mA
FIGURE 11 CIRCUIT
3851A G08
Start-Up with Prebiased Output
at 2V
V_OUT
2V/DIV
V_FB
0.5V/DIV
TK/SS
0.5V/DIV
20ms/DIV
3851A G09
Coincident Tracking with Master
Supply
V_MASTER
0.5V/DIV
V_OUT
2A LOAD
0.5V/DIV
10ms/DIV
3851A G10
3851afa
5