LTC3521 Datasheet, PDF (4/20 Pages) Linear Technology – Wide VIN, 1A Buck-Boost DC/DC and Dual 600mA Buck DC/DC Converters

LTC3521
Typical Performance Characteristics T_A = 25°C, unless otherwise noted.
Buck-Boost Efficiency,
Li-Ion to 3.3V
100
V_IN = 2.7V PWM MODE
140
90
V_IN = 4.2V
120
80
70
100
60
80
50
Burst Mode
40 OPERATION
60
30
40
20
10
0
0.1
Burst Mode
20
POWER LOSS
0
1
10
100
1000
LOAD CURRENT (mA)
3521 G01
Buck Efficiency, Li-Ion to 2.5V
100
V_IN = 3.6V
90
V_IN = 4.2V
80
Burst Mode
70
OPERATION
60
50
40
140
PWM MODE ₁₂₀
100
80
60
30
Burst Mode
40
20
POWER LOSS
20
10
0
0.1
1
0
10
100
1000
LOAD CURRENT (mA)
3521 G02
Buck Efficiency, Li-Ion to 1.8V
100
V_IN = 2.7V
90
V_IN = 4.2V
80 ^{Burst Mode}
OPERATION
70
140
PWM MODE 120
100
60
80
50
40
60
30
Burst Mode
40
20
POWER LOSS
20
10
0
0
0.1
1
10
100
1000
LOAD CURRENT (mA)
3521 G03
Buck Burst Mode Current Threshold
60
50
V_OUT = 1.2V
40
30
20
V_OUT = 1.8V
10 _{VOUT = 2.5V}
0
1.5 2 2.5 3 3.5 4 4.5 5 5.5
V_IN (V)
3521 G04
Buck-Boost Switches R_DS(ON)
160
V_IN = 3.6V
140 ^{VOUT1 = 3.3V}
120
PMOS
(SWITCHES A AND D)
100
NMOS
80
(SWITCHES B AND C)
60
40
20
0
–40 –20
0 20 40 60 80
TEMPERATURE (°C)
100 120
3521 G05

Buck Switches R_DS(ON)
350
V_IN = 3.6V
300
PMOS
250
NMOS
200
150
100
50
0
–40 –20
0 20 40 60 80
TEMPERATURE (°C)
100 120
3521 G06
Switching Frequency
vs Temperature
1.0
0.8
0.6
0.4
0.2
0
–0.2
–0.4
–0.6
–0.8
–1.0
–50 –30 –10 10 30 50 70 90 110
TEMPERATURE (°C)
3521 G07
3521f