LTC3869-2_15 Datasheet, PDF (5/42 Pages) Linear Technology – Dual, 2-Phase Synchronous Step-Down DC/DC Controllers

LTC3869/LTC3869-2
Typical Performance Characteristics T_A = 25°C, unless otherwise noted.
Efficiency vs Output Current
and Mode
100
90
Burst Mode
80 OPERATION
70
60
DCM
50
V_IN = 12V
V_OUT = 1.8V
40
CCM
30
20
10
0
0.01
CIRCUIT OF FIGURE 16
0.1
1
10
LOAD CURRENT (A)
100
3869 G01
Efficiency vs Output Current
and Mode
100
90
80 ^{Burst Mode}
OPERATION
70
60
DCM
50
V_IN = 12V
V_OUT = 1.2V
40
CCM
30
20
10
0
0.01
CIRCUIT OF FIGURE 16
0.1
1
10
LOAD CURRENT (A)
100
3869 G02
Full Load Efficiency and Power
Loss vs Input Voltage
90
5
1.8V
EFFICIENCY
1.2V
85
4
1.8V
80
POWER LOSS
3
1.2V
CIRCUIT OF FIGURE 16
75
5
10
15
INPUT VOLTAGE (V)
2
20
3869 G03
Load Step
(Burst Mode Operation)
I_LOAD
5A/DIV
300mA TO 5A
I_L
5A/DIV
V_OUT
100mV/DIV
AC-COUPLED
V_IN = 12V
V_OUT = 1.8V
50µs/DIV
Load Step
(Forced Continuous Mode)
I_LOAD
5A/DIV
300mA TO 5A
Load Step
(Pulse-Skipping Mode)
I_LOAD
5A/DIV
300mA TO 5A
I_L
5A/DIV
I_L
5A/DIV
V_OUT
100mV/DIV
AC-COUPLED
3869 G04
V_IN = 12V
V_OUT = 1.8V
50µs/DIV
V_OUT
100mV/DIV
AC-COUPLED
3869 G05
V_IN = 12V
V_OUT = 1.8V
50µs/DIV
3869 G06
Inductor Current at Light Load
FORCED
CONTINUOUS
MODE
5A/DIV
Burst Mode
OPERATION
5A/DIV
PULSE-
SKIPPING
MODE
5A/DIV
V_IN = 12V
V_OUT = 1.8V
I_LOAD = 400mA
1µs/DIV
3869 G07
Prebiased Output at 2V
V_OUT
2V/DIV
V_FB
500mV/DIV
TK/SS
500mV/DIV
V_IN = 12V
V_OUT = 3.3V
2ms/DIV
3869 G08
For more information www.linear.com/LTC3869
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