原标题：NS LM21215 15A高效同步降压电源解决方案

　　NS 公司的LM21215是15A高效同步降压电源稳压器,输入电压从2.95V 到 5.5V,输出电压可低至0.6V.器件集成了7.0 mΩ 高边和4.3 mΩ 低边FET 开关,固定工作频率500kHz,输出电压具有跟踪功能,可调整软起动,并集成了OVP,OTP,UVLO和电源良好,主要用在宽带,窄带和无线通信,高性能FPGA,ASIC和微处理器等.本文介绍了LM21215主要特性, 方框图, 简化应用电路图和两种典型应用电路和相应的材料清单.

　　LM21215 : 15A High Efficiency Synchronous Buck Regulator

　　The LM21215 is a monolithic synchronous buck regulator that is capable of delivering up to 15A of continuous output current while producing an output voltage down to 0.6V with outstanding efficiency. The device is optimized to work over an input voltage range of 2.95V to 5.5V, making it suited for a wide variety of low voltage systems. The voltage mode control loop provides high noise immunity, narrow duty cycle capability and can be compensated to be stable with any type of output capacitance, providing maximum flexibility and ease of use.

　　The LM21215 features internal over voltage protection (OVP) and resistor-programmable over-current protection (OCP) for increased system reliability. A precision enable pin and integrated UVLO allow turn-on of the device to be tightly controlled and sequenced. Startup inrush currents are limited by both an internally fixed and externally adjustable soft-start circuit. Fault detection and supply sequencing are possible with the integrated power good circuit.

　　The LM21215 is designed to work well in multi-rail power supply architectures. The output voltage of the device can be configured to track an external voltage rail using the SS/TRK

　　pin. If the output is pre-biased at startup, it will not sink current, allowing the output to smoothly rise past the pre-biased voltage.

　　The regulator is offered in a 20-pin eTSSOP package with an exposed pad that can be soldered to the PCB, eliminating the need for bulky heatsinks.

　　LM21215主要特性:

　　■ Integrated 7.0 mΩ high side and 4.3 mΩ low side FET switches

　　■ Adjustable current limit

　　■ Adjustable output voltage from 0.6V to VIN (100% duty cycle capable), ±1% reference

　　■ Input voltage range 2.95V to 5.5V

　　■ 500 kHz fixed switching frequency

　　■ Startup into pre-biased loads

　　■ Output voltage tracking capability

　　■ Wide bandwidth voltage loop error amplifier

　　■ Adjustable soft-start with external capacitor

　　■ Precision enable pin with hysteresis

　　■ Integrated OVP, OTP, UVLO and Power-Good

　　■ Thermally Enhanced eTSSOP-20 exposed pad package

　　LM21215应用:

　　■ Broadband, networking and wireless communications

　　■ High-performance FPGAs, ASICs and microprocessors

　　■ Simple to design, high efficiency point of load regulation from a 5V or 3.3V bus

　　图1.LM21215方框图

　　图2.LM21215简化应用电路图

　　图3.LM21215典型应用电路图(1)

　　材料清单(VIN = 3.3 - 5.5V, VOUT = 1.2V, IOUT = 15A)

　　图4.LM21215典型应用电路图(2)

　　材料清单(VIN = 4.0 - 5.5V, VOUT = 0.9V, IOUT = 8A)