LTC3554-2_15 Datasheet, PDF (10/36 Pages) Linear Technology – Micropower USB Power Manager with Li-Ion Charger and Two Step-Down Regulators

LTC3554/LTC3554-1/
LTC3554-2/LTC3554-3
Typical Performance Characteristics T_A = 25°C, unless otherwise specified.
Step-Down Switching
Regulator Switch Impedance
vs Temperature
1.6
BV_IN = 3.2V
1.4 ^{STBY = L}
PMOS
1.2
1.0
NMOS
0.8
0.6
0.4
0.2
0
–75 –50 –25 0 25 50 75 100 125 150
TEMPERATURE (°C)
3554 G20
Step-Down Switching
Regulator Feedback Voltage
vs Output Current
0.820
0.815
3.8V
5V
STBY = L
0.810
0.805
Step-Down Switching Regulator
Start-Up Waveform
V_OUT2
50mV/DIV
(AC)
V_OUT1
1V/DIV
0.800
0.795
0.790
0.785
0.780
0.1
1
10
100
OUTPUT CURRENT (mA)
0V
I_L1
100mA/DIV
0mA
PWR_ON1
1000
3554 G21
V_OUT2 = 1.2V
I_OUT2 = 50mA
R_OUT1 = 22Ω
STBY = L
100µs/DIV
3554 G28
Step-Down Switching
Regulator Output Transient
(FSEL Low to High)
Step-Down Switching
Regulator Output Transient (STBY
High to Low)
V_OUT1
50mV/DIV
(AC)
V_OUT2
20mV/DIV
(AC)
FSEL
V_OUT1 = 3.3V
I_OUT1 = 100mA
V_OUT2 = 1.2V
I_OUT2 = 50mA
STBY = L
50µs/DIV
V_OUT1
20mV/DIV
(AC)
V_OUT2
20mV/DIV
(AC)
STBY
3554 G29
V_OUT1 = 3.3V
I_OUT1 = 5mA
V_OUT2 = 1.2V
I_OUT2 = 5mA
50µs/DIV
3554 G30
Step-Down Switching Regulator
Dropout Voltage in Standby Mode
vs Load Current
200
V_BVIN = 2.9V
180 V_FBx = 780mV
160
–45°C
25°C
140
90°C
STBY = H
120
100
80
60
40
20
0
0 2 4 6 8 10 12 14
LOAD CURRENT (mA)
3554 G23
10
3554123ff