LTC3531 Datasheet, PDF (1/16 Pages) Linear Technology – 200mA Buck-Boost Synchronous DC/DC Converters

LTC3531/
LTC3531-3.3/LTC3531-3
200mA Buck-Boost
Synchronous DC/DC
Converters
FEATURES
■ _{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}
Current <1μA
■ _{Only 3 External Components Required}
(Fixed Voltage Versions)
■ _{Short-Circuit Protection}
■ _{Output Disconnect in Shutdown}
■ _{Available in 6-Pin ThinSOT and 3mm × 3mm DFN}
Packages
U
APPLICATIO S
■ _{Handheld Instruments}
■ _{MP3 Players}
■ _{Handheld computers}
■ _PDA/GPS
DESCRIPTIO
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
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 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.
TYPICAL APPLICATIO
V_IN
3.1V TO
4.2V
Li-Ion
10μH
SW1 SW2
V_IN
V_OUT
LTC3531-3.3
2.2μF
SHDN GND
ON OFF
V_OUT
3.3V
160mA
10μF
3531 TA01a
Efficiency vs V_IN
100
95
90
BOOST
MODE
85
BUCK
MODE
80
4SW
75
MODE
70
65
3.3V_OUT AT 100mA
60
1.5 2 2.5 3 3.5 4 4.5 5 5.5
INPUT VOLTAGE (V)
3531 TA01b
3531fb
1