LTC3550 Datasheet, PDF (7/24 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.
HPWR Pin Pull-Down Resistance
vs Temperature
2.8
2.6
2.4
2.2
2.0
1.8
1.6
–50 –25
0 25 50
TEMPERATURE (°C)
75 100
3550 G45
Recharge Threshold Voltage
vs Temperature
4.16
4.14
4.12
V_DCIN = V_USBIN = 4.3V
4.10
V_DCIN = V_USBIN = 8V
4.08
4.06
4.04
–50
–25 0 25 50
TEMPERATURE (°C)
75 100
3550 G20
Buck Regulator Efficiency
vs V_CC
100
95
I_OUT = 100mA
90
I_OUT = 10mA
85 ^{IOUT = 1mA}
80
I_OUT = 600mA
75
70
I_OUT = 0.1mA
65
60
55
50 ^{VOUT = 1.8V}
2
3
4
5
6
V_CC (V)
3550 G23
EN Pin Pull-Down Resistance
vs Temperature
2.8
2.6
2.4
2.2
2.0
1.8
1.6
–50 –25
0 25 50
TEMPERATURE (°C)
75 100
3550 G18
Undervoltage Lockout Threshold
vs Temperature
4.25
4.20
DCIN UVLO
4.15
4.10
4.05
4.00
USBIN UVLO
3.95
3.90
3.85
–50
–25 0 25 50
TEMPERATURE (°C)
75 100
3550 G19
Battery Drain Current
vs Temperature
5
V_BAT = 4.2V
V_DCIN, V_USBIN (NOT CONNECTED)
4
3
Charge Current During Turn-On
and Turn-Off
I_BAT
500mA/DIV
2
1
ENABLE
5V/DIV
0
–1
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
3550 G21
Buck Regulator Efficiency
vs Output Current
95
V_OUT = 1.8V
90
V_CC = 2.7V
85
V_CC = 4.2V
80
V_CC = 3.6V
75
70
65
60
0.1
1
10
100
OUTPUT CURRENT (mA)
1000
3550 G24
V_DCIN = 5V
R_IDC = 1.25k
100µs/DIV
Buck Regulator Efficiency
vs Output Current
95
V_OUT = 1.5V
90
V_CC = 2.7V
85
V_CC = 4.2V
80
V_CC = 3.6V
75
3550 G22
70
65
60
0.1
1
10
100
OUTPUT CURRENT (mA)
1000
3550 G25
3550fa
7