LTC3533 Datasheet, PDF (1/16 Pages) Linear Technology – 2A Wide Input Voltage Synchronous Buck-Boost DC/DC Converter

FEATURES
■ _{Regulated Output with Input Voltages Above,}
Below or Equal to the Output
■ _{1.8V to 5.5V (Input) and 5.25V (Output)}
Voltage Range
■ _{0.8A Continuous Output Current: VIN > 1.8V}
■ _{2A Continuous Output Current: VIN > 3V}
■ _{Single Inductor}
■ _{Synchronous Rectification: Up to 96% Efficiency}
■ _{Programmable Burst Mode}^® _{Operation: IQ = 40µA}
■ _{Output Disconnect in Shutdown}
■ _{Programmable Frequency from 300kHz to 2MHz}
■ _{<1µA Shutdown Current}
■ _{Small Thermally Enhanced 14-Lead (3mm × 4mm ×}
0.75mm) DFN package
APPLICATIONS
■ _{GSM Modems}
■ _{Handheld Instruments}
■ _{Digital Cameras}
■ _{Smart Phones}
■ _{Media Players}
■ _{Miniature Hard Disk Drive Power}
LTC3533
2A Wide Input Voltage
Synchronous Buck-Boost
DC/DC Converter
DESCRIPTION
The LTC^®3533 is a wide V_IN range, highly efficient, fixed
frequency, buck-boost DC/DC converter that operates
from input voltages above, below or equal to the output
voltage. The topology incorporated in the IC provides a
continuous transfer function through all operating modes,
making the product ideal for single cell lithium-ion/polymer
or multi-cell alkaline/NiMH applications where the output
voltage is within the input voltage range.
The LTC3533 features programmable Burst Mode opera-
tion, extended V_IN and V_OUT ranges down to 1.8V, and
increased output current. Switching frequencies up to
2MHz are programmed with an external resistor. The Burst
Mode threshold is programmed with a single resistor from
the BURST pin to GND.
Other features include 1µA shutdown current, short
circuit protection, programmable soft-start, current limit
and thermal shutdown. The LTC3533 is housed in the
thermally enhanced 14-lead (3mm × 4mm × 0.75mm)
DFN package.
, LT, LTC, LTM and Burst Mode are registered trademarks of Linear Technology
Corporation. All other trademarks are the property of their respective owners.
TYPICAL APPLICATION
2.2µH
V_IN
2.4V TO 4.2V
OFF ON
10µF
SW1
SW2
PV_IN
V_IN
PV_OUT
V_OUT
LTC3533
RUN/SS
FB
R_T
V_C
330pF
107k
4.7pF
340k 6.49k
47pF
V_OUT
3.3V
1.5A
100µF
33.2k
SGND
BURST
PGND
0.1µF
200k
200k
3533 TA01
Efficiency
100
90
80 Burst Mode
OPERATION
70
60
50 ^{VIN = 2.9V}
V_IN = 2.2V
40
V_IN = 3.9V
30
20
10
0
0.1
1
10 100 1000 10000
OUTPUT CURRENT (mA)
3533 TA01b
3533f
1