Intersil公司的ISL8225M是一款全密封降压开关稳压功率器件，可以分别输出2路15A电流或单独1路30A电流，最高达到100W输出。外围电路仅需要几个器件就可以实现高密度、高可靠性的高性能电源解决方案。通过自动电流共享和相交差允许6个模块并连输出能力可达180A，输出电压精度为1.5%，差动远程电压传感和快速瞬态响应实现高性能的功率系统。为增强系统的可靠性，内建过压、过流和过温保护。本文首先介绍芯片的简介、特性、内部框图及应用领域，并给出相应设计方案的设计原理图、元器件列表及PCB元件布局图。

The ISL8225M is a fully-encapsulated step-down switching power supply that can deliver up to 100W output power from a small 17mm square PCB footprint. The two 15A outputs may be used independently or combined to deliver a single 30A output. Designing a high-performance board-mounted power supply has never been simpler -- only a few external components are needed to create a very dense and reliable power solution.

Automatic current sharing and phase interleaving allow up to six modules to be paralleled for 180A output capability. 1.5% output voltage accuracy, differential remote voltage sensing and fast transient response create a very high-performance power system. Built-in output over-voltage, over-current and over-temperature protection enhance system reliability.

The ISL8225M is available in a thermally-enhanced QFN package. Excellent efficiency and low thermal resistance permit full power operation without heat sinks or fans. In addition, the QFN package with external leads permits easy probing and visual solder inspection.

ISL8225M主要特性：

• Fully-encapsulated dual step-down switching power supply
• Up to 100W output from a 17mm square PCB footprint
• Dual 15A or single 30A output
• Up to 95% conversion efficiency
• 4.5V to 20V input voltage range
• 0.6V to 6V output voltage range
• 1.5% output voltage accuracy with differential remote sensing
• Up to six modules may be paralleled to support 180A output current
• Output over-voltage, over-current and over-temperature protection
• Full power operation without heat sinks or fans
• QFN package with exposed leads permits easy probing and visual solder inspection

ISL8225M应用：

• Computing, networking and telecom infrastructure equipment
• Industrial and medical equipment
• General purpose point-of-load (POL) power

图1. ISL8225M内部方框图

ISL8225M方案介绍：

The ISL8225M is a complete, dual step-down switching mode DC/DC module. The dual outputs can easily be paralleled for single-output, high-current use. It is easy to apply this high-power, current-sharing DC/DC power module to power-hungry datacom, telecom, and FPGA applications. All that is needed in order to have a complete, dual 15A design ready for use are the ISL8225M, a few passive components, and VOUT setting resistors.

The simplicity of the ISL8225M is its off-the-shelf, unassisted implementation. Patented current sharing in multi-phase operation greatly reduces ripple currents, BOM costs, and complexity. The ISL8225M has a thermally enhanced, compact 17mm x17mm x 7.5mm QFN package that operates at full load and over-temperature without requiring forced-air cooling. Easy access to all pins, with few external components, reduces PCB design to a component layer and a simple ground layer.

This ISL8225MEVAL4Z evaluation board is designed for dual 15A output applications. Optionally, this board can easily be converted for 30A single output use. Multiple ISL8225MEVAL4Z boards can be cascadable through the SYNC and CLKOUT pins to operate with phase shifting, for paralleling or multiple output use. The input voltage of this board is 4.5V to 20V and the default outputs on this board are set at 1.2V and 1.5V.

ISL8225M方案原理图：

图2. ISL8225M方案原理图

ISL8225M方案材料清单：



PCB元件布局图：