LTC3550_15 Datasheet, PDF (8/24 Pages) Linear Technology – Dual Input USB/AC Adapter Li-Ion Battery Charger with 600mA Buck Converter

LTC3550
TYPICAL PERFOR A CE CHARACTERISTICS T_A = 25°C, unless otherwise noted.
Buck Regulator Efficiency
vs Output Current
100
V_OUT = 2.5V
95
V_CC = 2.7V
90
V_CC = 3.6V
85
V_CC = 4.2V
80
75
70
65
60
0.1
1
10
100
OUTPUT CURRENT (mA)
1000
3550 G26
Oscillator Frequency vs V_CC
1.8
1.7
1.6
1.5
1.4
1.3
1.2
2
3
4
5
6
V_CC (V)
3550 G29
Buck Regulator Switches R_DS(0N)
vs Temperature
0.7
V_CC = 2.7V
0.6
V_CC = 4.2V ^{VCC = 3.6V}
0.5
0.4
0.3
0.2
0.1
0
–50
MAIN SWITCH
SYNCHRONOUS SWITCH
–25 0 25 50 75
TEMPERATURE (°C)
100 125
3550 G32
Buck Regulator Reference
Voltage vs Temperature
0.614
V_CC = 3.6V
0.609
0.604
0.599
0.594
0.589
0.584
–50 –25
0 25 50 75 100 125
TEMPERATURE (°C)
3550 G27
Buck Regulator Output Voltage
vs Load Current
1.844
V_CC = 3.6V
1.834
1.824
1.814
1.804
1.794
1.784
1.774
0 100 200 300 400 500 600 700 800 900
LOAD CURRENT (mA)
3550 G30
Buck Regulator Supply
Current vs V_CC
50
45
V_OUT = 1.875V
I_LOAD = 0A
40
35
30
25
20
15
10
5
0
2
3
4
5
V_CC (V)
6
3550 G33
Oscillator Frequency
vs Temperature
1.70
V_CC = 3.6V
1.65
1.60
1.55
1.50
1.45
1.40
1.35
1.30
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3550 G28
R_DS(ON) vs V_CC
0.7
0.6
0.5
MAIN
SWITCH
0.4
0.3
SYNCHRONOUS
SWITCH
0.2
0.1
0
0 12
3 45
V_CC (V)
67
3550 G31
Buck Regulator Supply Current
vs Temperature
50
V_CC = 3.6V
45 _{VOUT = 1.875V}
40 ^{ILOAD = 0A}
35
30
25
20
15
10
5
0
–50 –25
0 25 50 75 100 125
TEMPERATURE (°C)
3550 G34
3550fa
8