Micropower Buck Regulator with Integrated Boost and Catch Diodes

The LT3470 is a micropower step-down DC/DC converter that integrates a 300mA power switch, catch diode and boost diode into low profile 3mm × 2mm DD and ThinSOT™ packages. The LT3470 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 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, simplifying power management in battery-powered systems. Fast current limiting and hysteretic control protects the LT3470 and external components against shorted outputs, even at 40V input.

Vin Min Startup

Switch Current

LT3470

5.5V

300mA

LT3470A

4V

400mA

Applications

* Automotive Battery Regulation

* Power for Portable Products

* Distributed Supply Regulation

* Industrial Supplies

* Wall Transformer Regulation

* 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