Datasheet

LTC3891
6
3891fa
TYPICAL PERFORMANCE CHARACTERISTICS
INPUT VOLTAGE (V)
0
SUPPLY CURRENT (µA)
200
300
20 30 35 40 45 50 55 60 6515105 25
3891 G10
150
100
50
250
NO LOAD
300µA LOAD
FIGURE 12 CIRCUIT
TEMPERATURE (°C)
–75
4.0
EXTV
CC
AND INTV
CC
VOLTAGE (V)
4.2
4.6
4.8
5.0
6.0
5.4
–25
25 50 75
100
3891 G11
4.4
5.6
5.8
5.2
–50
0
125
150
INTV
CC
EXTV
CC
RISING
EXTV
CC
FALLING
Total Input Supply Current vs
Input Voltage
EXTV
CC
Switchover and INTV
CC
Voltages vs Temperature INTV
CC
Line Regulation
V
IN
= 12V
V
OUT
= 3.3V
I
LOAD
= 200µA
5µs/DIV
3891 G07
FORCED
CONTINUOUS
MODE
PULSE-SKIPPING
MODE
Burst Mode
OPERATION
1A/DIV
Inductor Current at Light Load Soft Start-Up Tracking Start-Up
FIGURES 12, 14 CIRCUITS
2ms/DIV
3891 G08
V
OUT
= 3.3V
2V/DIV
V
OUT
= 8.5V
2V/DIV
2ms/DIV
3891 G09
V
OUT
2V/DIV
MASTER
2V/DIV
INPUT VOLTAGE (V)
3.0
INTV
CC
VOLTAGE (V)
4.0
4.5
5.5
20 30 35 40 45 50 55 60 6515100 5 25
3891 G12
3.5
5.0
I
LOAD
= 10mA
Load Step
Burst Mode Operation
Load Step
Forced Continuous Mode
Load Step
Pulse-Skipping Mode
LOAD STEP = 100mA TO 3A
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
50µs/DIV
3891 G04
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
LOAD STEP = 100mA TO 3A
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
50µs/DIV
3891 G05
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV
LOAD STEP = 100mA TO 3A
V
IN
= 12V
V
OUT
= 3.3V
FIGURE 12 CIRCUIT
50µs/DIV
3891 G06
V
OUT
100mV/DIV
AC-
COUPLED
I
L
2A/DIV