YB1682 Schematic ( PDF Datasheet ) - YOBON TECHNOLOGIES

Teilenummer	YB1682
Beschreibung	2A 380KHz 20V PWM Buck DC/DC Converter
Hersteller	YOBON TECHNOLOGIES
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Gesamt 9 Seiten YB1682 2A 380KHz 20V PWM Buck DC/DC Converter Description The YB1682 is a 380 KHz fixed frequency monolithic step down switch mode regulator with a built in internal Power MOSFET. It achieves 2A continuous output current over a wide input supply range with excellent load and line regulation. The device includes a voltage reference, oscillation circuit, error amplifier, internal PMOS and etc. The PWM control circuit is able to adjust the duty ratio linearly from 0 to 100%. An enable function, an over current protection function and a short circuit protection function are built inside. An internal compensation block is built in to minimize external component count. The YB1682 serves as ideal power supply units for portable devices. Typical Application Circuit Features „ 2A Constant Output Current „ 140mΩ RDSON Internal Power PMOSFET Switch „ Up to 92% Efficiency „ Fixed 380KHz Frequency „ Wide 3.6V to 20V Input Voltage Range „ Output Adjustable from 1.222V to 18V „ Output Current Protection „ Built in Frequency Compensation „ Built in Thermal Shutdown Function „ Built in Current Limit Function „ SOP8 Package is Available „ The Minimum Dropout up to 0.3V „ Pb-free Package Applications „ White LED Backlighting „ Handheld PCs and PDAs „ Mobile Phone „ DSC and DV Flash Light Application Pin Configuration YB1682 Rev.1.0 Figure 1: Typical Application Circuit www.yobon.com.tw 1 YB1682 2A 380KHz 20V PWM Buck DC/DC Converter Thermal Considerations The SOP8 package needs a heat sink under most conditions. The size of the heat sink depends on the input voltage, the output voltage, the load current and the ambient temperature. The YB1682 junction temperature rises above ambient temperature for a 2A load and different input and output voltages. The data for these curves was taken with the YB1682 (SOP8 package) operating as a buck-switching regulator in an ambient temperature of 25 ºC (still air). These temperature rise numbers are all approximate and there are many factors that can affect these temperatures. Higher ambient temperatures require more heat sinking. For the best thermal performance, wide copper traces and generous amounts of printed circuit board copper should be used in the board layout.(Once exception to this is the output (switch) pin, which should not have large areas of copper.) Large areas of copper provide the best transfer of heat (lower thermal resistance) to the surrounding air, and moving air lowers the thermal resistance even further. Package thermal resistance and junction temperature rise numbers are all approximate, and there are many factors that will affect these numbers. Some of these factors include board size, shape, thickness, position, location, and even board temperature. Other factors are, trace width, total printed circuit copper area, copper Thick ness, single or double-sided, multi-layer board and the amount of solder on the board. The effectiveness of the PC board to dissipate heat also depends on the size, quantity and spacing of other components on the board, as well as whether the surrounding air is still or moving. Furthermore, some of these components such as the catch diode will add heat to the PC board and the heat can vary as the input voltage changes. For the inductor, depending on the physical size, type of core material and the DC resistance, it could either act as a heat sink taking heat away from the board, or it could add heat to the board. YB1682 Rev.1.0 www.yobon.com.tw 6 6 Page
Seiten	Gesamt 9 Seiten
PDF Download	[ YB1682 Schematic.PDF ]

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