Datasheet

LTC3859
7
3859fa
TYPICAL PERFORMANCE CHARACTERISTICS
Load Step (Buck)
Burst Mode Operation
Load Step (Buck)
Forced Continuous Mode
Load Step (Buck)
Pulse-Skipping Mode
Inductor Current at Light Load
(Buck) Soft Start-Up
Buck Regulated Feedback Voltage
vs Temperature
Effi ciency and Power Loss
vs Output Current (Buck)
Effi ciency
vs Output Current (Buck) Effi ciency vs Input Voltage (Buck)
OUTPUT CURRENT (A)
0.0001
EFFICIENCY (%)
POWER LOSS (mW)
100
90
70
50
30
10
80
60
40
20
0
10000
100
1
1000
10
0.1
1100.01
3859 G01
0.10.001
FIGURE 12 CIRCUIT
V
IN
= 10V, V
OUT
= 5V
CCM EFFICIENCY
PULSE-SKIPPING
EFFICIENCY
BURST LOSS
BURST EFFICIENCY
CCM LOSS
PULSE-SKIPPING
LOSS
OUTPUT CURRENT (A)
0.0001
EFFICIENCY (%)
100
90
70
50
30
10
80
60
40
20
0
1100.01
3859 G02
0.10.001
V
IN
= 10V
V
IN
= 20V
FIGURE 12 CIRCUIT
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
100
99
97
95
93
98
96
94
92
20 25 30 35 4010
3859 G03
155
FIGURE 12 CIRCUIT
V
OUT
= 5V
I
LOAD
= 4A
50µs/DIV
V
OUT
100mV/DIV
AC-COUPLED
I
L
2A//DIV
V
IN
= 12V
V
OUT
= 5V
FIGURE 12 CIRCUIT
3859 G04
50µs/DIV
V
OUT
100mV/DIV
AC-COUPLED
I
L
2A//DIV
V
IN
= 12V
V
OUT
= 5V
FIGURE 12 CIRCUIT
3859 G05
50µs/DIV
V
OUT
100mV/DIV
AC-COUPLED
I
L
2A//DIV
V
IN
= 12V
V
OUT
= 5V
FIGURE 12 CIRCUIT
3859 G06
2µs/DIV
FORCED
CONTINUOUS
MODE
Burst Mode
OPERATION
1A/DIV
PULSE-
SKIPPING
MODE
V
IN
= 10V
V
OUT
= 5V
I
LOAD
= 1mA
FIGURE 12 CIRCUIT
3859 G07
2ms/DIV
V
OUT2
2V/DIV
V
OUT1
2V/DIV
3859 G08
FIGURE 12 CIRCUIT
TEMPERATURE (°C)
–45
REGULATED FEEDBACK VOLTAGE (mV)
808
806
802
798
794
804
800
796
792
30 55 80 105 130–20
3859 G09
5