LT3470 Datasheet, PDF (1/16 Pages) Linear Integrated Systems – Micropower Buck Regulator with Integrated Boost and Catch Diodes

LT3470
Micropower Buck Regulator
with Integrated Boost and
Catch Diodes
FEATURES
■ _{Low Quiescent Current: 26µA at 12VIN to 3.3VOUT}
■ _{Integrated Boost and Catch Diodes}
■ _{Input Range: 4V to 40V}
■ _{Low Output Ripple: <10mV}
■ _{< 1µA in Shutdown Mode}
■ _{Output Voltage: 1.25V to 16V}
■ _{200mA Output Current}
■ _{Hysteretic Mode Control}
– Low Ripple Burst Mode^® Operation at Light Loads
– Continuous Operation at Higher Loads
■ _{Solution Size as Small as 50mm}²
■ _{Low Profile (1mm) ThinSOT Package}
U
APPLICATIO S
■ _{Automotive Battery Regulation}
■ _{Power for Portable Products}
■ _{Distributed Supply Regulation}
■ _{Industrial Supplies}
■ _{Wall Transformer Regulation}
DESCRIPTIO
The LT^®3470 is a micropower step-down DC/DC converter
that integrates a 300mA power switch, catch diode and
boost diode into a low profile (1mm) ThinSOT^TM package.
The LT3470 combines Burst Mode and continuous opera-
tion to allow the use of tiny inductor and capacitors while
providing a low ripple output to loads of up to 200mA.
With its wide input range of 4V to 40V, the LT3470 can
regulate a wide variety of power sources, from 2-cell
Li-Ion batteries to unregulated wall transformers and lead-
acid batteries. Quiescent current in regulation is just 26µA
in a typical application while a zero current shutdown
mode disconnects the load from the input source, simpli-
fying power management in battery-powered systems.
Fast current limiting and hysteretic control protects the
LT3470 and external components against shorted out-
puts, even at 40V input.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Burst Mode is a registered trademark of Linear Technology Corporation.
ThinSOT is a trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
V_IN
7V TO 40V
OFF ON
V_IN BOOST
LT3470
SHDN
SW
BIAS
2.2µF
FB
GND
0.22µF
33µH
22pF
604k
1%
200k
1%
V_OUT
5V
200mA
22µF
Efficiency and Power Loss vs Load Current
90
V_IN = 12V
80
1000
70
100
60
50
10
40
30
1
20
10
0.1
1
10
LOAD CURRENT (mA)
0.1
100
3470 TA02
3470f
1