■ Regulated Output with Input Above, Below or Equal
to the Output
■ Single Inductor
■ Up to 90% Efﬁciency
■ VIN Range: 1.8V to 5.5V
■ 200mA at 3.3VOUT from 3.6V Input
■ 125mA at 3VOUT from 2.5V Input
■ Fixed VOUT Versions (TSOT, DFN): 3.3V, 3V
■ Adjustable VOUT Version (DFN): 2V to 5V
■ Burst Mode® Operation, No External Compensation
■ Ultra Low Quiescent Current: 16μA, Shutdown
■ Only 3 External Components Required
(Fixed Voltage Versions)
■ Short-Circuit Protection
■ Output Disconnect in Shutdown
■ Available in 6-Pin ThinSOT and 3mm × 3mm DFN
■ Handheld Instruments
■ MP3 Players
■ Handheld computers
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 efﬁciency over a wide range of
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
ThinSOTTM package for ﬁxed voltage versions or a 3mm ×
3mm DFN package for ﬁxed and adjustable versions.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Protected by U.S. Patents including 6166527.
Efﬁciency vs VIN
3.3VOUT AT 100mA
1.5 2 2.5 3 3.5 4 4.5 5 5.5
INPUT VOLTAGE (V)