Datasheet

LTC3521
19
3521fb
For more information www.linear.com/LTC3521
Typical applicaTion
Dual Supercapacitor to 3.3V at 200mA, 1.8V at 50mA and 1.2V at
100mA Backup Power Supply
Converter Output Voltages Efficiency vs V
IN
+
PV
IN1
PV
IN2
SW2
SW3
FB2
FB3
V
OUT1
LTC3521
SHDN2
SHDN1
R1
1.0M
R3
137k
R4
68.1k
C1
22µF
C2
10µF
C4
4.7µF
1F
+
1F
L1
4.7µH
L2
4.7µH
V
OUT1
3.3V
200mA
V
OUT2
1.8V
50mA
R5
100k
R6
100k
C3
10µF
L3
4.7µH
V
OUT3
1.2V
100mA
V
IN
1.8V TO 5.5V
R2
221k
3521 TA02a
SHDN3
PWM
SW1A
SW1B
FB1
PGOOD2
PGOOD1
PGOOD3
PGND2GND
ON
OFF
PWM
BURST
PGND1A
PGND1B
V
IN
V
IN
(V)
1.8
EFFICIENCY (%)
76
84
92
2.8 3.8 4.8
100
72
80
88
96
3521 TA02c
V
OUT1
= 3.3V
I
OUT
= 200mA
V
OUT2
= 1.8V
I
OUT
= 50mA
V
OUT3
= 1.2V
I
OUT
= 100mA
50µs/DIV
V
IN
2V/DIV
V
OUT2
2V/DIV
V
OUT3
2V/DIV
V
OUT1
2V/DIV
3521 TA02b