LTC3521
22
3521fb
For more information www.linear.com/LTC3521
LINEAR TECHNOLOGY CORPORATION 2010
LT 0813 REV B • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
(408) 432-1900
●
FAX: (408) 434-0507
●
www.linear.com/LTC3521
relaTeD parTs
PART NUMBER DESCRIPTION COMMENTS
LTC3100 700mA I
SW
, 1.5MHz, Synchronous Step-Up, 250mA
Synchronous Step-Down DC/DC Converter and 100mA LDO
94% Efficiency, V
IN
: 0.7V to 5V, V
OUT(MAX)
= 5.25V, I
Q
= 15µA,
I
SD
< 1µA, 3mm × 3mm QFN-16 Package
LTC3101 Wide V
IN
, Multioutput DC/DC Converter and PowerPath™
Controller, 800mA Buck-Boost, Dual 350mA Buck
Converters, 50mA Always-On LDO
95% Efficiency, V
IN
: 1.8V to 5.5V, I
Q
= 38µA, Standby I
Q
= 15µA,
4mm × 4mm QFN-24 Package
LTC3409 600mA I
OUT
, 1.7MHz/2.6MHz, Synchronous Step-Down DC/
DC Converter
96% Efficiency, V
IN
: 1.6V to 5.5V, V
OUT(MIN)
= 0.6V, I
Q
= 65µA,
I
SD
< 1µA, DFN Package
LTC3441/LTC3442/
LTC3443
1.2A I
OUT
, 2MHz, Synchronous Buck-Boost DC/DC
Converter
95% Efficiency, V
IN
: 2.4V to 5.5V, V
OUT(MIN)
: 2.4V to 5.25V,
I
Q
= 50µA, I
SD
< 1µA, DFN Package
LTC3520 1A 2MHz, Synchronous Buck-Boost and 600mA Buck
Converter
95% Efficiency, V
IN
: 2.2V to 5.5V, V
OUT(MAX)
= 5.25V, I
Q
= 55µA,
I
SD
< 1µA, 4mm × 4mm QFN-24 Package
LTC3522 400mA 2MHz, Synchronous Buck-Boost and 200mA Buck
Converter
95% Efficiency, V
IN
: 2.4V to 5.5V, V
OUT(MAX)
= 5.25V, I
Q
= 25µA,
I
SD
< 1µA, 3mm × 3mm QFN-16 Package
LTC3531/LTC3531-3/
LTC3531-3.3
200mA I
OUT
, 1.5MHz, Synchronous Buck-Boost DC/DC
Converter
95% Efficiency, V
IN
: 1.8V to 5.5V, V
OUT(MIN)
: 2V to 5V, I
Q
= 16µA,
I
SD
< 1µA, ThinSOT and DFN Packages
LTC3532 500mA I
OUT
, 2MHz, Synchronous Buck-Boost DC/DC
Converter
95% Efficiency, V
IN
: 2.4V to 5.5V, V
OUT(MIN)
: 2.4V to 5.25V,
I
Q
= 35µA, I
SD
< 1µA, MS10 and DFN Packages
LTC3547 Dual 300mA I
OUT
, 2.25MHz, Synchronous Step-Down DC/
DC Converter
95% Efficiency, V
IN
: 2.5V to 5.5V, V
OUT(MIN)
= 0.6V, I
Q
= 40µA,
I
SD
< 1µA, DFN-8 Package
Typical applicaTion
Li-Ion to 3.3V at 800mA, 1.8V at 600mA and 1.2V at
600mA with Sequenced Start-Up
Sequenced Start-Up Waveforms
PV
IN1
PV
IN2
SW2
V
OUT1
FB2
FB1
SW3
LTC3521
SHDN1
R5
100k
R3
137k
R4
68.1k
C3
10µF
C2
10µF
4.7µF
Li-Ion
L1
4.7µH
L3
4.7µH
L2
4.7µH
V
OUT2
1.8V
600mA
R1
1.0M
R2
221k
C1
22µF
V
OUT1
3.3V
800mA
(1A, V
IN
> 3.0V)
V
IN
2.4V TO
4.2V
R6
100k
499k
R5
499k
3521 TA03a
PGOOD1
PGOOD3
PWM
SW1A
SW1B
FB3
PGOOD2
SHDN2
SHDN3
PGOOD1
PGND2GND
PWM
BURST
ON
OFF
V
OUT3
1.2V
600mA
+
PGND1A
PGND1B
V
IN
500µs/DIV
V
OUT2
2V/DIV
V
OUT3
2V/DIV
V
OUT1
2V/DIV
SHDN2, 5V/DIV
PGOOD2, 5V/DIV
PGOOD3, 5V/DIV
3521 TA03b
