LTC3534_15 Datasheet, PDF (1/20 Pages) Linear Technology – 7V, 500mA Synchronous Buck-Boost DC/DC Converter

Features
n _{Regulated Output with Input Voltages Above,}
Below or Equal to the Output
n _{2.4V to 7V VIN and 1.8V to 7V VOUT Ranges}
n _{5V VOUT at 500mA from 4 AA Cells}
n _{Single Inductor}
n _{Synchronous Rectification: Up to 94% Efficiency}
n _{Burst Mode}^® _{Operation with 25µA IQ}
n _{Output Disconnect in Shutdown}
n _{1MHz Switching Frequency}
n _{<1µA Shutdown Current}
n _{Small Thermally Enhanced 16-Lead (5mm × 3mm ×}
0.75mm) DFN and 16-Lead GN Packages
Applications
n _{Medical Instruments}
n _{Portable Barcode Readers}
n _{Portable Inventory Terminals}
n _{USB to 5V Supply}
n _{Handheld GPS}
LTC3534
7V, 500mA Synchronous
Buck-Boost DC/DC
Converter
Description
The LTC^®3534 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 multi-cell Alkaline/NiMH or
single Lithium-Ion/Polymer applications where the output
voltage is within the battery voltage range.
The LTC3534 offers extended V_IN and V_OUT ranges of 2.4V
to 7V and 1.8V to 7V, respectively. Quiescent current is
only 25µA in Burst Mode operation, maximizing battery
life in portable applications. Burst Mode operation is user
controlled and can be enabled by driving the PWM pin
low. If the PWM pin is driven high then fixed frequency
switching is enabled.
Other features include fixed 1MHz operating frequency, a
<1µA shutdown, short-circuit protection, programmable
soft-start, current limit and thermal overload protection.
The LTC3534 is available in the thermally enhanced 16-lead
(3mm × 5mm) DFN and 16-lead GN packages.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
Burst Mode is a registered trademark of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Typical Application
4 AA Cells to 5V at 500mA Buck-Boost Converter
5µH
V_IN
3.6V TO 6.4V _{4 AA +}
CELLS 10µF
OFF ON
BURST PWM
SW1
SW2
PV_IN
V_OUT
V_IN
LTC3534
FB
RUN/SS
10k
33pF
15k
PWM
V_C
PGND1 GND PGND2 _330pF
649k
162k
3534 TA01a
V_OUT
5V
22µF ^500mA
4 AA Cells to 5V Efficiency vs V_IN
100
95
PWM I_OUT = 300mA
90
PWM I_OUT = 500mA
85
80
75
3.6 4.0 4.4 4.8 5.2 5.6 6.0 6.4
V_IN (V)
3534 TA01b
For more information www.linear.com/LTC3534
3534fb
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