原标题：Fairchild FAN5365 6MHz数字编程电源稳压方案

　　Fairchild 公司的FAN5365是1A/0.8A的6MHz数字编程电源稳压器,输出电压可从I2C接口调整,6位VOUT从0.75V到1.975V,支持800A或1A的负载电流,支持智能手机,数据卡,手持计算机中的低压DSP和处理器,核电源和存储器模块.6MHz的效率高达88%,VIN从2.3V到 5.5V,具有极好的负载和线路瞬态响应特性,PWM模式的DC电压精度±2%,主要用在3G, WiFi®, WiMAX™和WiBro® 数据卡,上网本,平板电脑等.本文介绍了FAN5365主要特性,方框图, 典型应用框图和推荐的外接元件.

　　FAN5365: 1A / 0.8A, 6MHz Digitally Programmable Regulator

　　The FAN5365 is a high-frequency, ultra-fast transient response, synchronous step-down, DC-DC converter optimized for low-power applications using small, low-cost inductors and capacitors. The FAN5365 supports up to 800mA or 1A load current.

　　The FAN5365 is ideal for mobile phones and similar portable applications powered by a single-cell Lithium-Ion battery.

　　With an output voltage range adjustable via I2C™ interface from 0.75V to 1.975V, it supports low-voltage DSPs and processors, core power supplies, and memory modules in smart phones, data cards, and hand-held computers.

　　The FAN5365 operates at 6MHz (nominal) fixed switching frequency in PWM mode.During light-load conditions, the regulator includes a PFM mode to enhance light-load efficiency. The regulator transitions smoothly between PWM and PFM modes with no glitches on VOUT. In hardware shutdown, the current consumption is reduced to less than 200nA.

　　The serial interface is compatible with fast / standard mode, fast mode plus, and high-speed mode I2C specifications, allowing transfers up to 3.4Mbps. This interface is used for dynamic voltage scaling with 12.5mV voltage steps, for reprogramming the mode of operation (PFM or forced PWM), or to disable/enable the output voltage.

　　The chip’s advanced protection features include short-circuit protection and current and temperature limits. During a sustained over-current event, the IC shuts down and restarts after a delay to reduce average power dissipation into a fault.

　　During startup, the IC controls the output slew rate to minimize input current and output overshoot at the end of soft-start. The IC maintains a consistent soft-start ramp, regardless of output load during startup.

　　The FAN5365 is available in a 1.27 x 1.29mm, 9-bump WLCSP package.

　　FAN5365主要特性:

　　High Efficiency (>88%) at 6MHz

　　800mA or 1A Output Current

　　Regulation Maintained with VIN from 2.3V to 5.5V

　　6-Bit VOUT Programmable from 0.75 to 1.975V

　　6MHz Fixed-Frequency Operation (PWM Mode)

　　Excellent Load and Line Transient Response

　　Small Size, 470nH Inductor Solution

　　±2% DC Voltage Accuracy in PWM Mode

　　25ns Minimum On-Time

　　High-Efficiency, Low-Ripple, Light-Load PFM

　　Smooth Transition between PWM and PFM

　　40μA Operating PFM Quiescent Current

　　I2C™-Compatible Interface up to 3.4Mbps

　　Pin-Selectable or I2C™ Programmable Output Voltage

　　9-Bump, 1.27 x 1.29mm, 0.4mm Pitch WLCSP Package

　　FAN5365应用:

　　3G, WiFi®, WiMAX™, and WiBro® Data Cards

　　Netbooks®, Ultra-Mobile PCs

　　SmartReflex™-Compliant Power Supply

　　Split Supply DSPs and μP Solutions OMAP™, XSCALE™

　　Handset Graphic Processors (NVIDIA®, ATI)

　　图1.FAN5365方框图

　　图2.FAN5365典型应用框图

　　推荐的外接元件: