Dual Synchronous 800mA, 2.25MHz Step-Down DC/DC Regulator

The LTC3407A-2 is a dual, constant frequency, synchronous step-down DC/DC converter. Intended for low power applications, it operates from a 2.5V to 5.5V input voltage range and has a constant 2.25MHz switching frequency, enabling the use of tiny, low cost capacitors and inductors 1mm or less in height. Each output voltage is adjustable from 0.6V to 5V. Internal synchronous 0.35Ω, 1A power switches provide high efficiency without the need for external Schottky diodes.

A user selectable mode input is provided to allow the user to trade-off ripple noise for low power efficiency. Burst Mode® operation provides the highest efficiency at light loads, while Pulse Skip Mode provides the lowest ripple noise at light loads.

To further maximize battery life, the P-channel MOSFETs are turned on continuously in dropout (100% duty cycle), and both channels draw a total quiescent current of only 40µA. In shutdown, the device draws <1µA.

IOUT

FSW

Features

LTC3407

2x 600mA

1.5MHz

LTC3407-2

2x 800mA

2.25MHz

LTC3407-3

2x 800mA

2.25MHz

Fixed 1.8V/3.3V

LTC3407-4

2x 800mA

2.25MHz

Reduced POR Delay

LTC3407A

2x 800mA

1.5MHz

Low Ripple Burst Mode

LTC3407A-2

2x 800mA

2.25MHz

Low Ripple Burst Mode

Applications

* PDAs/Palmtop PCs

* Digital Cameras

* Cellular Phones

* Wireless and DSL Modems

* High Efficiency: Up to 95%

* Low Ripple (<35mVPK-PK) Burst Mode Operation; IQ = 40µA

* 2.25MHz Constant Frequency Operation

* No Schottky Diodes Required

* Low RDS(ON) Internal Switches: 0.35Ω

* Current Mode Operation for Excellent Line and Load Transient Response

* Short-Circuit Protected