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LTC3531/
LTC3531-3.3/LTC3531-3
1
3531f
FEATURES
DESCRIPTIO
U
APPLICATIO S
U
TYPICAL APPLICATIO
U
INPUT VOLTAGE (V)
1.5
EFFICIENCY (%)
80
90
5.5
3531 TA01b
70
60
2.5
3.5
4.5
2
3
4
5
100
75
85
65
95
BOOST
MODE
4SW
MODE
3.3V
OUT
AT 100mA
BUCK
MODE
The LTC
®
3531/LTC3531-3.3/LTC3531-3 are synchronous
buck-boost DC/DC converters that operate from input
voltages above, below or equal to the output voltage. The
topology incorporated in the ICs provides a continuous
transfer through all operating modes, making the product
ideal for single cell Li-Ion and multicell alkaline or nickel
applications. The converters operate in Burst Mode, mini-
mizing solution footprint and component count as well as
providing high conversion effi ciency over a wide range of
load currents.
The devices include two 0.5Ω N-channel MOSFET switches
and two P-channel switches (0.5Ω, 0.8Ω). Quiescent
current is typically 16µA, making the parts ideal for bat-
tery power applications. Other features include a <1µA
shutdown current, current limiting, thermal shutdown
and output disconnect. The parts are offered in a 6-pin
ThinSOT
TM
package for fi xed voltage versions or a 3mm ×
3mm DFN package for fi xed and adjustable versions.
200mA Buck-Boost
Synchronous DC/DC
Converters
■
Regulated Output with Input Above, Below or Equal
to the Output
■
Single Inductor
■
Up to 90% Effi ciency
■
V
IN
Range: 1.8V to 5.5V
■
200mA at 3.3V
OUT
from 3.6V Input
■
125mA at 3V
OUT
from 2.5V Input
■
Fixed V
OUT
Versions (TSOT, DFN): 3.3V, 3V
■
Adjustable V
OUT
Version (DFN): 2V to 5V
■
Burst Mode
®
Operation, No External Compensation
■
Ultra Low Quiescent Current: 16µA, Shutdown
Current <1µA
■
Only 3 External Components Required
■
Short-Circuit Protection
■
Output Disconnect in Shutdown
■
Available in 6-Pin ThinSOT and 3mm × 3mm DFN
Packages
Effi ciency vs V
IN
■
Handheld Instruments
■
MP3 Players
■
Handheld computers
■
PDA/GPS
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Burst Mode is a registered trademark of Linear Techonology Corporation.
ThinSOT is a trademark of Linear Techonology Corporation.
Protected by U.S. Patents including 6166527.
SW1 SW2
SHDN GND
V
IN
V
OUT
LTC3531-3.3
2.2µF
10µF
ON OFF
Li-Ion
10µH
V
IN
3.1V TO
4.2V
V
OUT
3.3V
160mA
3531 TA01a
+
