Datasheet

LTC3520
7
3520fa
V
IN
(V)
2.2
OUTPUT CURRENT (mA)
3.7
3520 G17
2.7 3.2 4.2 4.7 5.2
0
20
40
60
80
100
120
140
V
OUT
= 3.3V
V
OUT
= 5V
V
IN
(V)
2.2
OUTPUT CURRENT (mA)
3.7
3520 G16
2.7 3.2 4.2 4.7 5.2
0
400
600
800
1000
1200
1400
1600
1800
200
V
OUT
= 5V
V
OUT
= 3.3V
Buck-Boost Maximum
Output Current, PWM Mode
Buck-Boost Maximum Output
Current, Burst Mode Operation
Buck-Boost PWM Mode
Effi ciency vs Frequency
Buck Effi ciency vs Frequency
Buck-Boost Burst Mode Operation
Buck Burst Mode Operation
TYPICAL PERFORMANCE CHARACTERISTICS
85
100
75
95
80
70
90
SWITCHING FREQUENCY (MHz)
0.4
EFFICIENCY (%)
0.8
1.2
1.6
0.6
1
2
1.4
1.8
3520 G19
V
IN
= 2.5V
V
OUT
= 1.8V
I
LOAD
= 100mA
L = 4.7μH SUMIDA
CDRH3D16NP
L = 2.2μH
SUMIDA
CDRH3D16NP
L = 8.2μH
COILCRAFT
MSS6132
SWITCHING FREQUENCY (MHz)
0.4
EFFICIENCY (%)
85
100
0.8
1.2
1.6
75
95
80
70
90
0.6
1
2
1.4
1.8
3520 G18
L = 8.2μH COILCRAFT
MSS6132
V
IN
= 3.6V
V
OUT
= 3.3V
I
LOAD
= 200mA
L = 4.7μH COILCRAFT
MSS7341
L = 2.2μH
COILCRAFT
1812PS
20μs/DIV
V
OUT
50mV/DIV
INDUCTOR
CURRENT
200mA/DIV
3520 G21
C
OUT
= 22μF
L = 4.7μH
I
LOAD
= 25mA
V
IN
= 3.6V
10μs/DIV
BUCK V
OUT
50mV/DIV
INDUCTOR
CURRENT
200mA/DIV
3520 G22
V
IN
= 3.6V
V
OUT
= 1.8V
I
LOAD
= 10mA
R
BURST
= 249k
C
OUT
= 10μF
LDO Output Voltage vs
Load Current
Buck-Boost Output Voltage vs
Load Current
LOAD CURRENT (mA)
0
–0.5
CHANGE IN VOLTAGE FROM ZERO LOAD (%)
0.5
0.4
0.3
0.2
0.1
–0.4
–0.3
–0.2
–0.1
0
400200 600 800
1000 1200
3520 G24
T
A
= –40°C
T
A
= 25°C
T
A
= 125°C
LOAD CURRENT (mA)
0
–0.20
CHANGE IN VOLTAGE FROM ZERO LOAD (%)
0.20
0.15
0.10
0.05
–0.15
–0.10
–0.05
0
100
200
300
3520 G25
T
A
= –40°C
T
A
= 25°C
T
A
= 125°C