LT3470
Micropower Buck Regulator
with Integrated Boost and
Catch Diodes
FEATURES
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DESCRIPTIO
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Low Quiescent Current: 26
µ
A at 12V
IN
to 3.3V
OUT
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
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.
APPLICATIO S
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Automotive Battery Regulation
Power for Portable Products
Distributed Supply Regulation
Industrial Supplies
Wall Transformer Regulation
TYPICAL APPLICATIO
V
IN
7V TO 40V
V
IN
OFF ON
SHDN
BOOST
Efficiency and Power Loss vs Load Current
90
V
IN
= 12V
1000
0.22µF
LT3470
SW
BIAS
22pF
2.2µF
FB
GND
200k
1%
604k
1%
22µF
33µH
V
OUT
5V
200mA
80
70
100
EFFICIENCY (%)
60
50
40
30
20
10
0.1
0.1
1
10
LOAD CURRENT (mA)
100
3470 TA02
U
POWER LOSS (mW)
10
1
3470f
U
U
1
LINEAR [ LINEAR INTEGRATED SYSTEMS ]
