LTC3444 - Micropower Synchronous Buck-Boost DC/DC Converter for WCDMA Applications

The LTC3444 has been optimized for use in 3G WCDMA applications. A unique design yields high efficiency at very low output voltages while also eliminating external components. The high speed error amplifier provides the fast transient response required to slew the RF power amplifier from standby to transmit and transmit to stand by power levels. Output overvoltage protection protects the RF power amplifier.

Operating frequency is internally set to 1.5MHz to minimize external component size while maximizing efficiency. Other features include <1μA shutdown current, internal soft-start, peak current limit and thermal shutdown.

The LTC3444 is available in a small, thermally enhanced 8-lead (3mm × 3mm) DFN package.

Features

Optimized Features for WCDMA Handsets
Regulated Output with Input Voltages Above, Below, or Equal to the Output
0.5V to 5V Output Range
Up to 400mA Continuous Output Current From a Single Lithium-Ion Cell
Minimal External Components
1.5MHz Fixed Frequency Operation
Internal Loop Compensation for Fast Response <25μs Full Scale Output Slewing; COUT 4.7μF
Output Disconnect in Shutdown
2.75V to 5.5V Input
<1μA Shutdown Current
Internal Soft-Start
Output Overvoltage Protection
Single Inductor, No Schottky Diodes Required
Small, Thermally Enhanced 8-Lead (3mm × 3mm) DFN Package

Typical Application

Applications

WCDMA Applications–3G Handsets with High Speed Data Rate Capability
MP3 Players
Digital Cameras

Packaging

Order Information

Part Number	Package	Temp	Price(1-99)	Price (1k)*
LTC3444EDD#PBF	3x3 DFN-8	E	$3.43	$2.40
LTC3444EDD#TRPBF	3x3 DFN-8	E		$2.46

Demo Boards

Part Number	Description	Price
DC901A	LTC3444EDD Demo Board \| Synchronous Buck-Boost, for CDMA & HSDPA, 3.1V ≤VIN ≤ 5V, Vout = 0.8V to 4.2V @ 400mA	$100.00