LTC3875_15 Datasheet, PDF (5/44 Pages) Linear Technology – Dual, 2-Phase, Synchronous Controller with Low Value DCR Sensing and Temperature Compensation

LTC3875
Typical Performance Characteristics
Efficiency vs Output Current and
Mode (Figure 16 Application Circuit)
100
90 ^{Burst Mode}
OPERATION
80
70
60
CCM
50
PULSE-SKIPPING
40
30
20
10
0
0.01
V_IN = 12V
V_OUT = 1.5V
0.1
1
10
100
LOAD CURRENT (A)
3875 G01
Load Step
(Figure 16 Application Circuit)
(Forced Continuous Mode)
Efficiency vs Output Current and
Mode (Figure 16 Application Circuit)
100
Load Step
(Figure 16 Application Circuit)
(Burst Mode Operation)
90
80
Burst Mode
70 _OPERATION
60
CCM
50
I_LOAD
40A/DIV
5A TO 30A
I_L1, I_L2
10A/DIV
40
30
20
10
0
0.01
PULSE-
SKIPPING
V_OUT
100mV/DIV
AC-COUPLED
V_IN = 12V
V_OUT = 1V
V_IN = 12V
V_OUT = 1.5V
0.1
1
10
100
LOAD CURRENT (A)
10µs/DIV
3875 G03
3875 G02
Load Step
(Figure 16 Application Circuit)
(Pulse-Skipping Mode)
Prebiased Output at 1V
I_LOAD
40A/DIV
5A TO 30A
I_L1, I_L2
10A/DIV
V_OUT
100mV/DIV
AC-COUPLED
V_IN = 12V
V_OUT = 1.5V
10µs/DIV
I_LOAD
40A/DIV
5A TO 30A
I_L1, I_L2
10A/DIV
V_OUT
100mV/DIV
AC-COUPLED
3875 G04
V_IN = 12V
V_OUT = 1.5V
10µs/DIV
V_OUT
1V/DIV
V_OSNS+
500mV/DIV
TK/SS
500mV/DIV
3875 G05
V_IN = 12V
V_OUT = 1.5V
CCM: NO LOAD
2.5ms/DIV
3875 G06
Coincident Tracking
RUN
2V/DIV
V_OUT1
V_OUT1
V_OUT2
1V/DIV
V_OUT2
V_IN = 12V
2.5ms/DIV
V_OUT1 = 1.5V, R_LOAD = 12Ω, CCM
V_OUT2 = 1V, R_LOAD = 6Ω, CCM
3875 G07
Tracking Up and Down
with External Ramp
TK/SS1
TK/SS2
2V/DIV
V_OUT2
V_OUT1
V_OUT2
500mV/DIV
V_OUT1
V_IN = 12V
10ms/DIV
V_OUT1 = 1V, 1Ω LOAD
V_OUT2 = 1.5V, 1.5Ω LOAD
3875 G08
Quiescent Current
vs Temperature without EXTV_CC
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
–50 –30 –10 10 30 50 70 90 110 130
TEMPERATURE (°C)
3875 G09
For more information www.linear.com/LTC3875
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