特点
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
典型应用
典型应用
描述
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.