LTC3899_15 Datasheet, PDF (7/38 Pages) Linear Technology – 60V Low IQ, Triple Output, Buck/Buck/Boost Synchronous Controller

Typical Performance Characteristics
LTC3899
Efficiency and Power Loss
vs Output Current (Buck)
100
BURST EFFICIENCY
90
10000
80
70
FCM LOSS
60 ^{PULSE-SKIPPING}
LOSS
50
PULSE-SKIPPING
40 EFFICIENCY
30
1000
100
BURST LOSS
10
FCM EFFICIENCY
20
10
0
0.0001
0.001 0.01
FIGURE 12 CIRCUIT ¹
V_IN = 10V
V_OUT = 5V _0.1
0.1
1
10
OUTPUT CURRENT (A)
3899 G01
Efficiency
vs Output Current (Buck)
100
90
80
70
V_IN = 10V
V_IN = 20V
60
V_IN = 30V
50
40
30
20
10
0
0.0001
FIGURE 12 CIRCUIT
V_OUT = 5V
Burst Mode OPERATION
0.001 0.01 0.1
1
OUTPUT CURRENT (A)
10
3899 G02
Efficiency vs Input Voltage (Buck)
98
96
94
DRVSET = INTV_CC
92
DRVSET = 0V
90
88
86
84
FIGURE 12 CIRCUIT
82 ^VOUT ^{= 5V}
I_LOAD = 4A
80
0 10 20 30 40
INPUT VOLTAGE (V)
50 60
3899 G03
Load Step (Buck)
Burst Mode Operation
Load Step (Buck)
Pulse-Skipping Mode
Load Step (Buck)
Forced Continuous Mode
V_OUT
100mV/DIV
AC COUPLED
V_OUT
100mV/DIV
AC COUPLED
V_OUT
100mV/DIV
AC COUPLED
I_L
2A/DIV
I_L
2A/DIV
I_L
2A/DIV
50µs/DIV
V_IN = 12V
V_OUT = 5V
FIGURE 12 CIRCUIT
3899 G04
50µs/DIV
V_IN = 12V
V_OUT = 5V
FIGURE 12 CIRCUIT
3899 G05
50µs/DIV
V_IN = 12V
V_OUT = 5V
FIGURE 12 CIRCUIT
3899 G06
Inductor Current at Light Load
(Buck)
FORCED
CONTINUOUS
MODE
Burst Mode
OPERATION
1A/DIV
PULSE-
SKIPPING
MODE
2µs/DIV
V_IN = 12V
V_OUT = 5V
I_LOAD = 1mA
FIGURE 12 CIRCUIT
3899 G07
Soft Start-Up (Buck)
2ms/DIV
FIGURE 12 CIRCUIT
RUN1, 2
5V/DIV
V_OUT2
2V/DIV
V_OUT1
2V/DIV
3899 G08
Buck Regulated Feedback Voltage
vs Temperature
808
806
804
802
800
798
796
794
792
-75 -50 -25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3899 G09
3899f
For more information www.linear.com/LTC3899
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