Datasheet

LTC3859AL
7
3859alf
For more information www.linear.com/3859AL
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)
Buck Regulated Feedback Voltage
vs Temperature
Efficiency and Power Loss
vs Output Current (Buck)
Efficiency
vs Output Current (Buck) Efficiency 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
1 100.01
3859al G01
0.10.001
FIGURE 12 CIRCUIT
V
IN
= 10V, V
OUT
= 5V
FCM EFFICIENCY
PULSE-SKIPPING
EFFICIENCY
BURST LOSS
BURST EFFICIENCY
FCM LOSS
PULSE-SKIPPING
LOSS
OUTPUT CURRENT (A)
0.0001
EFFICIENCY (%)
100
90
70
50
30
10
80
60
40
20
0
1 100.01
3859al G02
0.10.001
V
IN
= 10V
V
IN
= 20V
FIGURE 12 CIRCUIT
V
OUT
= 5V
INPUT VOLTAGE (V)
0
EFFICIENCY (%)
100
99
97
95
93
98
96
94
92
20 25 30 35 4010
3859al 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
3859al G04
50µs/DIV
V
OUT
100mV/DIV
AC-COUPLED
I
L
2A//DIV
V
IN
= 12V
V
OUT
= 5V
FIGURE 12 CIRCUIT
3859al G05
50µs/DIV
V
OUT
100mV/DIV
AC-COUPLED
I
L
2A//DIV
V
IN
= 12V
V
OUT
= 5V
FIGURE 12 CIRCUIT
3859al 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
3859al G07
5ms/DIV
V
OUT2
2V/DIV
V
OUT1
2V/DIV
RUN1/
RUN2
5V/DIV
3859al G08
V
IN
= 12V
FIGURE 12 CIRCUIT
TEMPERATURE (°C)
–75
REGULATED FEEDBACK VOLTAGE (mV)
808
806
802
798
794
804
800
796
792
0 25 50 75 150125100–50
3859al G09
–25