Datasheet
LTC3677-3
13
36773f
Step-Down Switching Regulator 2
1.8V Output Efficiency vs I
OUT2
Step-Down Switching Regulator 3
1.2V Output Efficiency vs I
OUT3
Step-Down Switching Regulator 3
2.5V Output Efficiency
Step-Down Switching Regulator
Short-Circuit Current vs Temperature
I
OUT
(mA)
0.01
40
EFFICIENCY (%)
50
60
70
80
0.1 1 10 100 1000
36773 G21
30
20
10
0
90
100
V
IN12
= 3.8V
V
IN12
= 5V
Burst Mode
OPERATION
PULSE-SKIPPING
V
OUT2
= 1.8V
I
OUT
(mA)
0.01
40
EFFICIENCY (%)
50
60
70
80
0.1 1 10 100 1000
36773 G22
30
20
10
0
90
100
V
IN3
= 3.8V
V
IN3
= 5V
Burst Mode
OPERATION
PULSE-SKIPPING
V
OUT3
= 1.2V
I
OUT
(mA)
0.01
40
EFFICIENCY (%)
50
60
70
80
0.1 1 10 100 1000
36773 G23
30
20
10
0
90
100
V
IN3
= 3.8V
V
IN3
= 5V
Burst Mode
OPERATION
PULSE-SKIPPING
V
OUT3
= 2.5V
TEMPERATURE (°C)
–50
SHORT-CIRCUIT CURRENT (mA)
1100
25
36773 G24
800
600
–25 0 50
500
1200
1300
1400
1500
1000
900
700
75 100 125
800mA BUCK
500mA BUCK
V
INx
= 3.8V
V
INx
= 5V
Typical perForMance characTerisTics
Step-Down Switching Regulator
Output Transient (Burst Mode
Operation)
Step-Down Switching Regulator
Output Transient (Pulse-Skipping)
800mA Step-Down Switching
Regulator Feedback Voltage
vs Output Current
T
J
= 25°C unless otherwise specified
Step-Down Switching Regulator
Switch Impedance vs Temperature
TEMPERATURE (°C)
–50
0
SWITCH IMPEDANCE (Ω)
0.1
0.3
0.4
0.5
50
0.9
36773 G27
0.2
0
–25
75 100
25 125
0.6
0.7
0.8
800mA NMOS
800mA PMOS
500mA
PMOS
500mA
NMOS
V
INX
= 3.2V
I
OUT
(mA)
0.78
FEEDBACK (V)
0.84
0.85
0.77
0.76
0.83
0.80
0.82
0.81
0.79
0.1 10 100 1000
357732 G29
0.75
1
V
IN3
= 3.8V
V
IN3
= 5V
Burst Mode
OPERATION
PULSE-SKIPPING
V
OUT1
50mV/DIV
(AC)
V
OUT2
50mV/DIV
(AC)
V
OUT3
100mV/DIV
(AC)
I
OUT3
500mA
5mA
36773 G25
50µs/DIVV
OUT1
= 3.3V
I
OUT1
= 10mA
V
OUT2
= 1.8V
I
OUT2
= 20mA
V
OUT3
= 1.2V
V
OUT
= V
BAT
= 3.8V
V
OUT1
50mV/DIV
(AC)
V
OUT2
50mV/DIV
(AC)
V
OUT3
100mV/DIV
(AC)
I
OUT3
500mA
5mA
36773 G26
50µs/DIVV
OUT1
= 3.3V
I
OUT1
= 30mA
V
OUT2
= 1.8V
I
OUT2
= 20mA
V
OUT3
= 1.2V
V
OUT
= V
BAT
= 3.8V
500mA Step-Down Switching
Regulator Feedback Voltage
vs Output Current
I
OUT
(mA)
0.78
FEEDBACK (V)
0.84
0.85
0.77
0.76
0.83
0.80
0.82
0.81
0.79
0.1 10 100 1000
36773 G29
0.75
1
Burst Mode
OPERATION
PULSE-SKIPPING
V
IN12
= 3.8V
V
IN12
= 5V