LTC3531/
LTC3531-3.3/LTC3531-3
200mA Buck-Boost
Synchronous DC/DC
Converters
U
FEATURES
■
■
■
■
■
■
■
■
■
■
■
■
■
■
DESCRIPTIO
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
■
■
■
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 battery 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.
Handheld Instruments
MP3 Players
Handheld computers
PDA/GPS
U
■
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, minimizing solution footprint and component count as well as
providing high conversion efficiency over a wide range of
load currents.
TYPICAL APPLICATIO
Efficiency vs VIN
100
10μH
95
Li-Ion
VIN
+
SW2
VOUT
LTC3531-3.3
2.2μF
VOUT
3.3V
160mA
10μF
SHDN
EFFICIENCY (%)
90
SW1
VIN
3.1V TO
4.2V
BOOST
MODE
85
BUCK
MODE
80
4SW
MODE
75
GND
70
3531 TA01a
65
ON OFF
60
1.5
3.3VOUT AT 100mA
2
2.5
3 3.5 4 4.5
INPUT VOLTAGE (V)
5
5.5
3531 TA01b
3531fb
1
