LTC3577-4_15 Datasheet, PDF (13/52 Pages) Linear Technology – Highly Integrated Portable Product PMIC

LTC3577-3/LTC3577-4
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise specified
Step-Down Switching Regulator
Short-Circuit Current vs Temperature
Step-Down Switching Regulator
Output Transient (Burst Mode
Operation)
Step-Down Switching Regulator
Output Transient (Pulse-Skipping)
1500
1400
1300
1200
1100
1000
900
800
700
600
500
–50 –25
V_OUT1
50mV/DIV
(AC)
800mA BUCK
V_OUT2
50mV/DIV
(AC)
V_OUT3
100mV/DIV
(AC)
500mA BUCK
500mA
I_{OUT3 5mA}
V_INx = 3.8V
V_INx = 5V
0 25 50 75 100 125
TEMPERATURE (°C)
357734 G25
V_OUT1 = 3.3V
50μs/DIV
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)
357734 G26
500mA
I_{OUT3 5mA}
V_OUT1 = 3.3V
50μs/DIV
I_OUT1 = 30mA
V_OUT2 = 1.8V
I_OUT2 = 20mA
V_OUT3 = 1.2V
V_OUT = V_BAT = 3.8V
357734 G27
800mA Step-Down Switching
500mA Step-Down Switching
Step-Down Switching Regulator
Regulator Feedback Voltage
Regulator Feedback Voltage
Switch Impedance vs Temperature
vs Output Current
vs Output Current
0.9
0.85
0.85
V_INX = 3.2V
0.8
0.84
0.84
0.7
500mA
500mA
PMOS
0.83
0.82
0.6 _NMOS
0.81
0.5
0.80
0.4
800mA PMOS
0.79
0.3
800mA NMOS
0.78
0.2
0.77
Burst Mode
OPERATION
PULSE-SKIPPING
0.83
0.82
Burst Mode
0.81
OPERATION
0.80
PULSE-SKIPPING
0.79
0.78
0.77
0.1
0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
357734 G28
0.76
0.75
0.1
V_IN3 = 3.8V
V_IN3 = 5V
1
10
100
1000
I_OUT (mA)
357732 G29
0.76
0.75
0.1
V_IN12 = 3.8V
V_IN12 = 5V
1
10
100
1000
I_OUT (mA)
357734 G30
Step-Down Switching Regulator 3
Soft-Start and Shutdown
OVP Connection Waveform
V_OUT1
100mV/DIV
(AC)
2V
V_OUT3 1V
0V
400mA
I_L3 200mA
0mA
V_OUT1 = 1.8V
I_OUT1 = 100mA
R_OUT3 = 3Ω
50μs/DIV
V_BUS
5V/DIV
OVGATE
5V/DIV
OVP
INPUT
VOLTAGE
0V TO 5V
357734 G31 _{STEP 5V/DIV}
500μs/DIV
OVP Protection Waveform
V_BUS
5V/DIV
OVGATE
5V/DIV
357734 G32
OVP
INPUT
VOLTAGE
5V TO 10V
STEP 5V/DIV
500μs/DIV
357734 G33
357734fb
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