Datasheet

LTC3809-1
4
38091fc
TYPICAL PERFORMANCE CHARACTERISTICS
LOAD CURRENT (mA)
EFFICIENCY (%)
100
90
80
70
95
85
75
65
60
1 100 1k 10k
38091 G01
10
V
OUT
= 3.3V
V
OUT
= 2.5V
V
OUT
= 1.8V
V
OUT
= 1.2V
FIGURE 8 CIRCUIT
MODE = V
IN
V
IN
= 5V
LOAD CURRENT (mA)
EFFICIENCY (%)
100
90
80
70
95
85
75
65
50
55
60
38091 G02
1 100 1k 10k10
FIGURE 8 CIRCUIT
V
IN
= 5V, V
OUT
= 2.5V
FORCED
CONTINUOUS
(MODE = 0V)
PULSE SKIPPING
(MODE = 0.6V)
BURST MODE
(MODE = V
IN
)
I
TH
VOLTAGE (V)
0.5
–20
CURRENT LIMIT (%)
0
20
40
60
100
1 1.5
38091 G03
2
80
Burst Mode OPERATION
(I
TH
RISING)
Burst Mode OPERATION
(I
TH
FALLING)
FORCED CONTINUOUS
MODE
PULSE SKIPPING
MODE
V
OUT
200mV/DIV
AC COUPLED
I
L
2A/DIV
100μs/DIV
V
IN
= 3.3V
V
OUT
= 1.8V
I
LOAD
= 300mA TO 3A
MODE = V
IN
FIGURE 8 CIRCUIT
38091 G04
V
OUT
200mV/DIV
AC COUPLED
I
L
2A/DIV
100μs/DIV
V
IN
= 3.3V
V
OUT
= 1.8V
I
LOAD
= 300mA TO 3A
MODE = 0V
FIGURE 8 CIRCUIT
38091 G05
V
OUT
200mV/DIV
AC COUPLED
I
L
2A/DIV
100μs/DIV
V
IN
= 3.3V
V
OUT
= 1.8V
I
LOAD
= 300mA TO 3A
MODE = V
FB
FIGURE 8 CIRCUIT
38091 G06
V
OUT
1.8V
500mV/DIV
200μs/DIV
V
IN
= 4.2V
R
LOAD
= 1
FIGURE 8 CIRCUIT
38091 G07
V
OUT
1.8V
500mV/DIV
1ms/DIV
V
IN
= 4.2V
R
LOAD
= 1
FIGURE 8 CIRCUIT
38091 G08
Load Step
(Burst Mode Operation)
Load Step
(Forced Continuous Mode)
Load Step
(Pulse-Skipping Mode)
Start-Up with Internal Soft-Start
(TRACK/SS = V
IN
)
Start-Up with External Soft-Start
(C
SS
= 10nF)
Effi ciency vs Load Current Effi ciency vs Load Current
Maximum Current Sense Voltage
vs I
TH
Pin Voltage
T
A
= 25°C, unless otherwise noted.