YB1682 Datasheet, PDF (6/9 Pages) YOBON TECHNOLOGIES,INC. – 2A 380KHz 20V PWM Buck DC/DC Converter

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