Datasheet

LTC3555/LTC3555-X
9
3555fd
TYPICAL PERFORMANCE CHARACTERISTICS
RST3, CHRG Pin Current vs
Voltage (Pull-Down State)
3.3V LDO Step Response
(5mA to 15mA)
R
DS(ON)
for Switching Regulator
Power Switches vs Temperature
Switching Regulator Current Limit
vs Temperature
Switching Regulator Low Power
Mode Quiescent Currents
Switching Regulator Soft-Start
Waveform
Battery Drain Current vs
Temperature
Switching Regulators 1, 2 Pulse
Skip Mode Quiescent Currents
Switching Regulator 3 Pulse Skip
Mode Quiescent Currents
RST3, CHRG PIN VOLTAGE (V)
0
RST3, CHRG PIN CURRENT (mA)
60
80
100
4
3555 G19
40
20
0
1
2
3
5
V
BUS
= 5V
BAT = 3.8V
I
LDO3V3
5mA/DIV
0mA
20µs/DIVBAT = 3.8V
3555 G20
V
LDO3V3
20mV/DIV
AC COUPLED
TEMPERATURE (°C)
–40
BATTERY CURRENT (µA)
30
40
50
60
3555 G21
20
10
0
–15
10
35
85
BAT = 3.8V
V
BUS
= 0V
BUCK REGULATORS OFF
TEMPERATURE (°C)
–40
ON-RESISTANCE (Ω)
0.6
0.8
1.0
60
3555 G22
0.4
0.2
0
–15
10
35
85
NMOS SWITCH
NMOS SWITCH
PMOS SWITCH
REGULATORS 1, 2
REGULATOR 3
PMOS SWITCH
TEMPERATURE (°C)
–40
CURRENT LIMIT (A)
1.0
1.5
60
3555 G23
0.5
0
–15
10
35
85
2.0
REGULATOR 3
REGULATORS 1, 2
V
IN1,2,3
= 3.8V
TEMPERATURE (°C)
–40
INPUT CURRENT (µA)
30
40
50
60
3555 G24
20
10
0
–15
10
35
85
V
IN1,2,3
= 3.8V
V
OUT1,2,3
= 2.5V
Burst Mode
OPERATION
LDO MODE
FORCED
Burst Mode
OPERATION
TEMPERATURE (°C)
–40
INPUT CURRENT (µA)
INPUT CURRENT (mA)
275
300
325
60
3555 G25
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
TEMPERATURE (°C)
–40
INPUT CURRENT (µA)
INPUT CURRENT (mA)
300
350
60
3555 G26
250
200
–15
10
35
85
400
9
10
8
7
11
V
IN3
= 3.8V
(PULSE
SKIPPING)
V
IN3
= 3.5V
(CONSTANT FREQUENCY)
V
OUT3
= 2.5V
V
OUT
500mV/DIV
50µs/DIV
3555 G27