Datasheet

LTC3556
10
3556f
TYPICAL PERFORMANCE CHARACTERISTICS
R
DS(ON)
’s for Switching Regulator 3
vs Temperature
Switching Regulator 3 Effi ciency
vs Load Current
Switching Regulator 3 PWM Mode
Effi ciency vs Input Voltage
Switching Regulators 1, 2 Load
Regulation at V
OUT1,2
= 2.5V
LOAD CURRENT (mA)
2.47
OUTPUT VOLTAGE (V)
2.50
2.53
2.56
0.1 10 100 1000
3556 G28
2.44
1
V
BUS
= 3.8V
Burst Mode OPERATION
FORCED
Burst Mode
OPERATION
PULSE SKIP MODE
Switching Regulator 3 Reduction in
Current Deliverability at Low V
IN3
V
IN3
(V)
2.7
0
REDUCTION BELOW 1A (mA)
50
100
150
200
300
3.1
3.5 3.9 4.3
3556 G34
4.7
250
START-UP WITH A
CURRENT SOURCE LOAD
STEADY STATE LOAD
V
OUT3
= 3.3V
T
A
= 27°C
START-UP WITH A
RESISTIVE LOAD
Switching Regulator 3 Burst Mode
Operation Input Quiescent Current
TEMPERATURE (°C)
–55
I
VIN3
(µA)
13.0
13.5
12.5
12.0
–15 5 45
–35
25 65
105
85 125
11.5
11.0
14.0
3556 G29
V
OUT3
= 3.3V
T
A
= 27°C
V
IN3
= 3V
V
IN3
= 4.5V
V
IN3
= 3.6V
V
IN3
= V
OUT3
= 3V
TEMPERATURE (°C)
–55
PMOS R
DS(ON)
()
0.20
0.25
0.15
0.10
–15 5 45
–35
25 65
105
85 125
0.05
0
0.30
NMOS R
DS(ON)
()
0.30
0.35
0.25
0.20
0.15
0.10
0.40
3556 G31
PMOS
NMOS
V
IN3
= V
OUT3
= 4.5V
V
IN3
= V
OUT3
= 3.6V
V
IN3
= 4.5V
V
IN3
= 3V
V
IN3
= 3.6V
TEMPERATURE (°C)
–55
I
LIMF3
(mA)
2500
2550
2450
2400
–15 5 45
–35
25 65
105
85 125
2350
2300
2600
3556 G30
V
IN3
= 3V
V
IN3
= 4.5V
V
IN3
= 3.6V
Switching Regulator 3 Forward
Current Limit vs Temperature
LOAD CURRENT (mA)
EFFICIENCY (%)
0.1 10 100 10001
3556 G32
V
OUT3
= 3.3V
T
A
= 27°C
V
IN3
= 3V
V
IN3
= 3.6V
V
IN3
= 4.5V
Burst Mode
OPERATION
CURVES
PWM MODE
CURVES
40
50
60
70
80
30
20
10
0
90
100
40
50
60
70
80
30
20
10
0
90
100
V
IN3
(V)
2.7
EFFICIENCY (%)
3.1
3.5 3.9 4.3
3556 G33
4.7
V
OUT3
= 3.3V
T
A
= 27°C
I
OUT3
= 200mA
I
OUT3
= 50mA
I
OUT3
= 1000mA