描述 Description

DESCRIPTIO U
The LTC?1267 series are dual synchronous step-down switching regulator controllers featuring automatic Burst ModeTM operation to maintain high efficiencies at low output currents. The LTC1267 is composed of two separate regulator blocks, each driving a pair of external complementary power MOSFETs at switching frequencies up to 400kHz. The LTC1267 uses a constant off-time current mode architecture to provide constant ripple current in the inductor and provide excellent line and load transient response.
A separate pin and on-board switch allow the MOSFET driver power to be derived from the regulated output voltage,providingsignificantefficiencyimprovementwhen operating at high input voltage. The output current level is user-programmable via an external current sense resistor.
The LTC1267 series is ideal for applications requiring dual output voltages with high conversion efficiencies over a wide load current range in a small amount of board space.FEATURES
■ Dual Outputs: 3.3V and 5V, Two Adjustables or Adjustable and 5V
■ Wide VIN Range: 4V to 40V
■ Ultra-High Efficiency: Up to 95%
■ Low Supply Current in Shutdown: 20mA
■ Current Mode Operation for Excellent Line and Load Transient Response
■ High Efficiency Maintained Over a Wide Output Current Range
■ Independent Micropower Shutdown
■ Very Low Dropout Operation: 100% Duty Cycle
■ Synchronous FET Switching for High Efficiency
■ Available in Standard 28-Pin SSOPAPPLICATIONS
■ Notebook and Palmtop Computers
■ Battery-Operated Digital Devices
■ Portable Instruments
■ DC Power Distribution Systems

特性 Features

■ Dual Outputs: 3.3V and 5V, Two Adjustables or Adjustable and 5V
■ Wide VIN Range: 4V to 40V
■ Ultra-High Efficiency: Up to 95%
■ Low Supply Current in Shutdown: 20mA
■ Current Mode Operation for Excellent Line and Load Transient Response
■ High Efficiency Maintained Over a Wide Output Current Range
■ Independent Micropower Shutdown
■ Very Low Dropout Operation: 100% Duty Cycle
■ Synchronous FET Switching for High Efficiency
■ Available in Standard 28-Pin SSOP

應(yīng)用 Application

■ Notebook and Palmtop Computers
■ Battery-Operated Digital Devices
■ Portable Instruments
■ DC Power Distribution Systems

簡(jiǎn)介

LTC1267屬于集成電路（IC）的PMIC-穩(wěn)壓器-DCDC開關(guān)式控制器。由制造生產(chǎn)的LTC1267DC-DC 開關(guān)控制器PMIC（電源管理集成電路）DC 到 DC 開關(guān)式控制器是用于高效率電路的穩(wěn)壓 IC，其配置為生成高于（突升或步升）或低于（突降或步降）輸入電源的輸出電源電壓。其他拓?fù)浣Y(jié)構(gòu)可能包括：降壓-升壓、反激、正激、Cuk、SEPIC、全橋、半橋和推挽式。這些器件不同于需要最小電壓并“燒盡”多余電壓的線性穩(wěn)壓器。