NS LM3102 2.5A降压稳压器解决方案

NS公司的LM3102是同步的SIMPLE SWITCHER降压稳压器，它的输出电流达2.5A，输出电压可低到0.8V，输入电压从4.5V到42V,开关频率为1MHz..本文介绍了LM3102的主要性能和特点，以及应用电路图和所用的元器件清单（BOM）.



LM3102 SIMPLE SWITCHER  Synchronous 1MHz 2.5A Step-Down Voltage Regulator

概述：
The LM3102 Synchronously Rectified Buck Converter features all required functions to implement a highly efficient and cost effective buck regulator. It is capable of supplying 2.5A to loads with an output voltage as low as 0.8V. Dual N-Channel synchronous MOSFET switches allow a low component count, thus reducing complexity and minimizing board size. Different from most other COT regulators, the LM3102 does not rely on output capacitor ESR for stability, and is designed to work exceptionally well with ceramic and other very low ESR output capacitors. It requires no loop compensation, results in a fast load transient response and simple circuit implementation. The operating frequency remains nearly constant with line variations due to the inverse relationship between the input voltage and the on-time. The operating frequency can be externally programmed up to 1 MHz. Protection features include VCC under-voltage lock-out, output over-voltage protection, thermal shutdown, and gate drive under-voltage lock-out. The LM3102 is available in the thermally enhanced eTSSOP-20 package.

主要指标：
■ Input voltage range 4.5V-42V
■ 2.5A output current
■ 0.8V, ±1.5% reference
■ Integrated dual N-Channel main and synchronous MOSFETs
■ Thermally enhanced eTSSOP-20 package

主要特性：
■ Low component count and small solution size
■ Stable with ceramic and other low ESR capacitors
■ No loop compensation required
■ High efficiency at a light load by DCM operation
■ Pre-bias startup
■ Ultra-fast transient response
■ Programmable soft-start
■ Programmable switching frequency up to 1 MHz
■ Valley current limit
■ Output over-voltage protection
■ Precision internal reference for an adjustable output voltage down to 0.8V
■ Thermal shutdown

典型应用：
■ 5VDC, 12VDC, 24VDC, 12VAC, and 24VAC systems
■ Embedded Systems
■ Industrial Control
■ Automotive Telematics and Body Electronics
■ Point of Load Regulators
■ Storage Systems
■ Broadband Infrastructure
■ Direct Conversion from 2/3/4 Cell Lithium Batteries Systems



图１.LM3102简化的功能方框图

详细性能请见数据表：

http://cache.national.com/ds/LM/LM3102.pdf



图２. LM3102 应用电路图

下表为应用电路所用元器件清单(BOM)：