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

The LTC3407-2 is a dual, constant frequency, synchronous step down DC/DC converter. Intended for low power applications, it operates from 2.5V to 5.5V input voltage range and has a constant 2.25MHz switching frequency, allowing the use of tiny, low cost capacitors and inductors with a profile ≤1.2mm. Each output voltage is adjustable from 0.6V to 5V. Internal synchronous 0.35Ω, 1.2A 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 noise ripple for low power efficiency. Burst Mode® operation provides high efficiency at light loads, while Pulse Skip Mode provides low noise ripple 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

Reduce POR Delay

LTC3407A

2x 600mA

1.5MHz

Low Ripple Burst Mode

LTC3407A-2

2x 800mA

2.25MHz

Low Ripple Burst Mode

APPLICATIONS

* PDAs/Palmtop PCs

* Digital Cameras

* Cellular Phones

* Portable Media Players

* PC Cards

* Wireless and DSL Modems

* High Efficiency: Up to 95%

* Very Low Quiescent Current: Only 40µA

* 2.25MHz Constant Frequency Operation

* High Switch Current: 1.2A on Each Channel

* No Schottky Diodes Required

* Low RDS(ON) Internal Switches: 0.35Ω

* Current Mode Operation for Excellent Line and Load Transient Response

* Short-Circuit Protected