原标题：Linear LT3070可编输出线性电源稳压方案

　　Linear 公司的LT3070是5A低噪音可编输出85mV压降的线性稳压器,具有低压超快UltraFast的瞬态响应特性, 0.01μF旁路电容能降低输出电压噪音到25uVRMS.数字可编输出电压从0.8V到1.8V,数字输出富余度为±1%, ±3% 或±5%,两个并联可输出10A电流,线路,负载和温度的调整率为+/-1%.1MHz的35dB,可用于FPGA和DSP电源,ASIC和微处理器电源,服务器和存储设备电源等.本文介绍了LT3070主要特性,方框图, 0.9V 5A 稳压器应用电路和1.5V - 1.2V 线性稳压器电路, 带VIOC降压控制的稳压器电路, 1V/10A点负载电流共享稳压器电路以及三输出(1V/10A,1.8V/5A和1.5V/2.5A)电源电路.

　　5A, Low Noise, Programmable Output, 85mV Dropout Linear Regulator

　　The LT3070 is a low voltage, UltraFast™ transient response linear regulator. The device supplies up to 5A of output current with a typical dropout voltage of 85mV.

　　A 0.01μF reference bypass capacitor decreases output voltage noise to 25μVRMS. The LT3070’s high bandwidth permits the use of low ESR ceramic capacitors, saving bulk capacitance and cost. The LT3070’s features make it ideal for high performance FPGAs, microprocessors or sensitive communication supply applications.

　　Output voltage is digitally selectable in 50mV increments over a 0.8V to 1.8V range. A margining function allows the user to tolerance system output voltage in increments of ±1%, ±3% or ±5%. The IC incorporates a unique tracking function to control a buck regulator powering the LT3070’s input. This tracking function drives the buck regulator to maintain the LT3070’s input voltage to VOUT + 300mV, minimizing power dissipation.

　　Internal protection includes UVLO, reverse-current protection, precision current limiting with power foldback and thermal shutdown. The LT3070 regulator is available in a thermally enhanced 28-lead,4mm.5mm QFN package.

　　LT3070主要特性:

　　Output Current: 5A

　　Dropout Voltage: 85mV Typical

　　Digitally Programmable VOUT : 0.8V to 1.8V

　　Digital Output Margining: ±1%, ±3% or ±5%

　　Low Output Noise: 25μVRMS (10Hz to 100kHz)

　　Parallelable: Use Two for a 10A Output

　　Precision Current Limit: ±10%

　　±1% Accuracy Over Line, Load and Temperature

　　Stable with Low ESR Ceramic Output Capacitors (15μF Minimum)

　　High Frequency PSRR: 35dB at 1MHz

　　Enable Function Turns Output On/Off

　　n VIOC Pin Controls Buck Converter to Maintain Low Power Dissipation and Optimize Effi ciency

　　PWRGD/UVLO Flag

　　Current Limit Foldback Protection

　　Thermal Shutdown

　　28-Lead (4mm 5mm) QFN Package

　　LT3070应用:

　　FPGA and DSP Supplies

　　ASIC and Microprocessor Supplies

　　Servers and Storage Devices

　　Post Buck Regulation and Supply Isolation

　　图1.LT3070方框图

　　图2.0.9V 5A 稳压器应用电路

　　图3.LT3070 1.5V - 1.2V 线性稳压器电路

　　图4.带VIOC降压控制的LT3070稳压器电路

　　图5.LT3070 1V/10A点负载电流共享稳压器电路

　　图6.三输出(1V/10A,1.8V/5A和1.5V/2.5A)电源电路