LT3470A Datasheet, PDF (1/20 Pages) Linear Technology – Micropower Buck Regulator with Integrated Boost and Catch Diodes

LT3470A
FEATURES
Micropower Buck Regulator
with Integrated Boost and
Catch Diodes
DESCRIPTION
n _{Low Quiescent Current: 35μA at 12VIN to 3.3VOUT}
n _{Integrated Boost and Catch Diodes}
n _{Input Range: 4V to 40V}
n _{3.3V at 250mA from 4V to 40V Input}
n _{5V at 250mA from 5.7V to 40V Input}
n _{Low Output Ripple: <10mV}
n _{< 1μA in Shutdown Mode}
n _{Output Voltage: 1.25V to 16V}
n _{Hysteretic Mode Control}
– Low Ripple Burst Mode^® Operation at Light Loads
– Continuous Operation at Higher Loads
n _{Solution Size as Small as 50mm}²
n _{Low Profile (0.75mm) 2mm × 3mm Thermally}
Enhanced 8-Lead DFN Package
APPLICATIONS
n _{Automotive Battery Regulation}
n _{Power for Portable Products}
n _{Distributed Supply Regulation}
n _{Industrial Supplies}
n _{Wall Transformer Regulation}
The LT^®3470A is a micropower step-down DC/DC con-
verter that integrates a 440mA power switch, catch diode
and boost diode into low profile 2mm × 3mm DFN
package. The LT3470A combines Burst Mode and
continuous operation to allow the use of tiny inductor
and capacitors while providing a low ripple output to
loads of up to 250mA.
With its wide input range of 4V to 40V, the LT3470A 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 35μA in
a typical application while a zero current shutdown mode
disconnects the load from the input source, simplifying
power management in battery-powered systems. Fast cur-
rent limiting and hysteretic control protects the LT3470A
and external components against shorted outputs, even
at 40V input. The LT3470A has higher output current and
improved start-up and dropout performance compared
to the LT3470.
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
V_IN
5.7V TO 40V
OFF ON
V_IN BOOST
LT3470A
SHDN
SW
BIAS
2.2μF
FB
GND
0.22μF
33μH
22pF
604k
1%
200k
1%
V_OUT
5V
250mA
22μF
3470a TA01
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
100
LOAD CURRENT (mA)
0.1
300
3470a TA02
3470afa
1