Datasheet

LTC3522
18
3522fa
TYPICAL APPLICATION
Li-Ion to 3V at 400mA and 1.2V at 200mA
+
PV
IN1
PV
IN2
SW2
FB2
V
OUT1
LTC3522
PGOOD2
1M
102k
12pF
100k
C2
4.7μF
C1
10μF
C3
4.7μF
Li-Ion
L2
4.7μH
L1
6.8μH
V
OUT1
3V
300mA
(400mA, V
IN
> 3V)
C1: MURATA GRM219R61A475K (0805 PACKAGE)
C2, C3: MURATA GRM21BR60J106K (0805 PACKAGE)
L1: TAIYO YUDEN NPO35B-6R8M
L2: TAIYO YUDEN NPO35B-4R7M
V
OUT2
1.2V
200mA
COMBINED
PGOOD
OUTPUT
V
IN
2.4V TO 4.2V
499k
3522 TA02
PGOOD1
PWM
SW1A
SW1B
FB1
SHDN2
SHDN1
PGND1 GND1 PGND2
499k
ON
OFF
PWM
BURST
Buck-Boost Converter Effi ciency vs Load Current Buck Converter Effi ciency vs Load Current
LOAD CURRENT (mA)
1
20
EFFICIENCY (%)
30
40
50
60
70
10
100
3522 TA02b
80
90
100
1000
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode
OPERATION
PWM Mode
LOAD CURRENT (mA)
1
30
EFFICIENCY (%)
40
50
60
70
10
100
3522 TA02c
80
90
100
1000
V
IN
= 4.2V
V
IN
= 2.7V
Burst Mode
OPERATION
PWM Mode