LTC3552 Datasheet, PDF (6/24 Pages) Linear Technology – Standalone Linear Li-Ion Battery Charger and Dual Synchronous Buck Converter

LTC3552
TYPICAL PERFOR A CE CHARACTERISTICS T_A = 25°C Unless Otherwise Specified.
Battery Charger
Power FET On-Resistance
vs Temperature
700
V_IN = 4.2V
650
I_BAT = 100mA
R_PROG = 2k
600
550
500
450
400
Recharge Threshold Voltage
vs Temperature
4.16
V_IN = 5V
R_PROG = 10k
4.14
4.12
4.10
4.08
4.06
350
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3552 G12
4.04
–50 –25 0
25 50
TEMPERATURE (°C)
75 100
3552 G13
Switching Regulator
Burst Mode Operation
Load Step
SW
5V/DIV
V_OUT
200mV/DIV
I_L
200mA/
DIV
V_OUT
RIPPLE
20mV/DIV
V_CC = 3.6V
2µs/DIV
V_OUT1 = 1.8V
I_LOAD = 60mA, MODE/SYNC = 3.6V
REGULATOR 1; CIRCUIT OF FIGURE 2
3552 G14
I_L
500mA/DIV
I_LOAD:
80mA-
800mA
500mA/DIV
V_CC = 3.6V
20µs/DIV
V_OUT1 = 1.8V
I_LOAD = 80mA TO 800mA
REGULATOR 1; CIRCUIT OF FIGURE 2
3552 G15
Pulse-Skipping Mode
SW
5V/DIV
V_OUT
10mV/
DIV
I_L
200mA
/DIV
V_CC = 3.6V
1µs/DIV
V_OUT1 = 1.8V
I_LOAD = 30mA, MODE/SYNC = 0V
REGULATOR 1; CIRCUIT OF FIGURE 2
3552 G16
Efficiency vs V_CC
100
95
90
85 _1mA
100mA
10mA
80 _800mA
75
70
65
V_OUT = 1.8V, REGULATOR 1
Burst Mode OPERATION
CIRCUIT OF FIGURE 2
60
2
3
4
5
V_CC (V)
6
3552 G17
6
Oscillator Frequency
vs Temperature
2.5
V_CC = 3.6V
2.4
2.3
2.2
2.1
2.0
–50 –25
0 25 50 75
TEMPERATURE (°C)
100 125
3552 G18
Oscillator Frequency
Error vs V_CC
10
8
6
4
2
0
–2
–4
–6
–8
–10
2
3
4
V_CC (V)
5
6
3552 G19
3552f