LTC3576-1_15 Datasheet, PDF (12/48 Pages) Linear Technology – Switching Power Manager with USB On-the-Go Triple Step-Down DC/DCs

LTC3576/LTC3576-1
TYPICAL PERFORMANCE CHARACTERISTICS T_A = 25°C unless otherwise specified.
Switching Regulator Constant
Frequency Quiescent Currents
8
7
SWITCHING
REGULATOR 3
6
5
4
3
SWITCHING
REGULATORS 1, 2
2
1
0
–40 –15 10
35
60
85
TEMPERATURE (°C)
3576 G46
Switching Regulators 1, 2
Feedback Voltage vs Load Current
0.820
Switching Regulator 3
Pulse-Skipping Mode Efficiency
100
V_IN3 = 3.8V
90
80
V_OUT3 = 2.5V
70
V_OUT3 = 1.8V
60
V_OUT3 = 1.2V
50
40
30
20
10
0
0.1
1
10
100
1000
LOAD CURRENT (mA)
3576 G47
Switching Regulators 1, 2
Transient Response
Switching Regulator 3
Burst Mode Efficiency
100
V_IN3 = 3.8V
90
V_OUT3 = 2.5V
80
V_OUT3 = 1.2V
70
60
V_OUT3 = 1.8V
50
40
30
20
10
0
0.1
1
10
100
1000
LOAD CURRENT (mA)
3576 G48
Switching Regulator Mode
Transition, Pulse-Skipping-LDO-
Pulse-Skipping
0.815
0.810
0.805
0.800
Burst Mode
OPERATION
PULSE-SKIPPING MODE
V_OUT2
50mV/DIV
AC COUPLED
I_OUT2
200mA/DIV
0mA
0.795
0.790
0.1
1
10
100
LOAD CURRENT (mA)
1000
3576 G49
V_IN2 = 3.8V
V_OUT2 = 3.4V
50μs/DIV
Switching Regulator 3 Feedback
Voltage vs Load Current
0.810
Switching Regulator 3
Transient Response
V_OUT3
50mV/DIV
AC COUPLED
3576 G50
V_SW3
1V/DIV
0V
V_IN3 = 3.8V
V_OUT3 = 1.8V
I_OUT3 = 50mA
50μs/DIV
3576 G51
Switching Regulator Mode
Transition, Pulse-Skipping–Burst
Mode Operation–Pulse-Skipping
0.805
0.800
0.795
0.790
0.1
Burst Mode
OPERATION
V_OUT3
50mV/DIV
AC COUPLED
PULSE-SKIPPING MODE
I_OUT3
500mA/DIV
0mA
1
10
100
LOAD CURRENT (mA)
1000
3576 G52
V_IN3 = 3.8V
V_OUT3 = 1.8V
50μs/DIV
12
V_OUT3
50mV/DIV
AC COUPLED
3576 G53
V_SW3
1V/DIV
0V
V_IN3 = 3.8V
V_OUT3 = 1.8V
I_OUT3 = 100mA
50μs/DIV
3576 G54
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