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On Semi公司的NCV890101是固定頻率降壓轉換器,內部集成了N溝功率開關,輸入電壓低至4.5V,高達36V,輸出電壓可調低至0.8V,誤差+/-1.75%,固定工作頻率2MHz,峰值電流1.4A,主要用在音頻,信息娛樂系統,儀表和安全視覺系統.本文介紹了NCV890101主要特性,方框圖,典型應用電路以及評估板NCV890101GEVB主要特性,電路圖,材料清單和PCB布局圖. The NCV890101 is a fixed−frequency, monolithic, Buck switching regulator intended for Automotive, battery−connected applications that must operate with up to a 36V input supply. The regulator is suitable for systems with low noise and small form factor requirements often encountered in automotive driver information systems.The NCV890101 is capable of converting the typical 4.5 V to 18 V automotive input voltage range to outputs as low as 3.3 V at a constant switching frequency above the sensitive AM band, eliminating the need for costly filters and EMI countermeasures. Two pins are provided to synchronize switching to a clock, or to another NCV890101. The NCV890101 also provides several protection features expected in Automotive power supply systems such as current limit, short circuit protection, and thermal shutdown. In addition, the high switching frequency produces low output voltage ripple even when using small inductor values and an all−ceramic output filter capacitor − forming a space−efficient switching regulator solution. NCV890101主要特性: Internal N−Channel Power Switch Low VIN Operation Down to 4.5 V High VIN Operation to 36 V Withstands Load Dump to 40 V 2 MHz Free−running Switching Frequency Auto−synchronizes with Other NCV890101 or to an External Clock Logic level Enable Input Can be Directly Tied to Battery 1.4 A (min) Cycle−by−Cycle Peak Current Limit Short Circuit Protection enhanced by Frequency Foldback +/-1.75% Output Voltage Tolerance Output Voltage Adjustable Down to 0.8 V 1.4 Millisecond Internal Soft−Start Thermal Shutdown (TSD) Low Shutdown Current NCV Prefix for Automotive and Other Applications Requiring Site and Change Controls Wettable Flanks DFN pb−Free Packages are Available NCV890101應用: Audio Infotainment Safety − Vision Systems Instrumentation 
圖1.NCV890101方框圖
圖2.NCV890101同步主從應用電路圖:電池使能
圖3.NCV890101外時鐘同步應用電路圖: 電池使能 NCV890101汽車級高頻降壓轉換器評估板NCV890101GEVB The NCV890101 demonstration board provides a convenient way to evaluate a high-frequency buck converter design. No additional components are required, other than dc supplies for the input and enable voltages. An external clock can be used to synchronize the switching frequency; and the board also provides a synchronization output, enabling it to be used as a master. It is configured for a 3.3 V output with a 2 MHz switching frequency and a 1.2 A maximum output current, over the typical 4.5 V to 18 V automotive input voltage range. In addition, the board regulates up to 36 V thanks to switching frequency foldback. 評估板NCV890101GEVB主要特性: • 3.3 V Output Voltage • 2 MHz Switching Frequency • 1.2 A Current Limit • Wide Input Voltage of 4.5 V to 36 V • Regulates through Load Dump Conditions • External Clock Synchronization up to 2.5 MHz • Synchronization Output • Automotive Grade
圖4. 評估板NCV890101GEVB外形圖
圖5. 評估板NCV890101GEVB電路圖 評估板NCV890101GEVB材料清單:
圖6. 評估板NCV890101GEVB PCB布局圖:頂層
圖7. 評估板NCV890101GEVB PCB布局圖:底層 詳情請見: 
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