LTC3556
9
3556f
TYPICAL PERFORMANCE CHARACTERISTICS
PGOODALL, CHRG Pin Current
vs Voltage (Pull-Down State)
3.3V LDO Step Response
(5mA to 15mA)
Battery Drain Current
vs Temperature
Switching Regulators 1, 2 Pulse
Skip Mode Quiescent Currents
PGOODALL, CHRG PIN VOLTAGE (V)
0
PGOODALL, CHRG PIN CURRENT (mA)
60
80
100
4
3556 G19
40
20
0
1
2
3
5
V
BUS
= 5V
BAT = 3.8V
I
LDO3V3
5mA/DIV
0mA
20µs/DIVBAT = 3.8V
3556 G20
V
LDO3V3
20mV/DIV
AC COUPLED
TEMPERATURE (°C)
–40
BATTERY CURRENT (µA)
30
40
50
60
3556 G21
20
10
0
–15
10
35
85
BAT = 3.8V
V
BUS
= 0V
ALL REGULATORS OFF
TEMPERATURE (°C)
–40
INPUT CURRENT (µA)
INPUT CURRENT (mA)
275
300
325
60
3556 G22
250
225
200
1.85
1.90
1.95
1.80
1.75
1.70
–15
10
35
85
V
OUT1,2
= 2.5V
(CONSTANT FREQUENCY)
V
OUT1,2
= 1.25V
(PULSE SKIPPING)
V
IN1,2
= 3.8V
Switching Regulators 1, 2
Pulse Skip Mode Effi ciency
Switching Regulators 1, 2
Burst Mode Effi ciency
Switching Regulators 1, 2
Forced Burst Mode Effi ciency
LOAD CURRENT (mA)
1
40
EFFICIENCY (%)
50
60
70
80
10 100 1000
3556 G23
30
20
10
0
90
100
V
OUT1,2
= 2.5V
V
OUT1,2
= 1.2V
V
OUT1,2
= 1.8V
V
IN1,2
= 3.8V
LOAD CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3556 G24
0
1
V
OUT1,2
= 2.5V
V
OUT1,2
= 1.2V
V
OUT1,2
= 1.8V
V
IN1,2
= 3.8V
LOAD CURRENT (mA)
30
EFFICIENCY (%)
90
100
20
10
80
50
70
60
40
0.1 10 100 1000
3556 G25
0
1
V
OUT1,2
= 2.5V
V
OUT1,2
= 1.2V
V
OUT1,2
= 1.8V
V
IN1,2
= 3.8V
Switching Regulators 1, 2 Load
Regulation at V
OUT1,2
= 1.2V
Switching Regulators 1, 2 Load
Regulation at V
OUT1,2
= 1.8V
LOAD CURRENT (mA)
1.185
OUTPUT VOLTAGE (V)
1.200
1.215
1.230
0.1 10 100 1000
3556 G26
1.170
1
V
BUS
= 3.8V
Burst Mode
OPERATION
FORCED
Burst Mode
OPERATION
PULSE SKIP
MODE
LOAD CURRENT (mA)
1.778
OUTPUT VOLTAGE (V)
1.800
1.823
1.845
0.1 10 100 1000
3556 G27
1.755
1
V
BUS
= 3.8V
Burst Mode OPERATION
FORCED
Burst Mode
OPERATION
PULSE SKIP MODE
