AP1501
150Khz, 3A PWM Buck DC/DC Converter
Function Description
(Continued)
The
AP1501
(TO-263
package)
junction
temperature rise above ambient temperature with a
2A load for various input and output voltages. This
data was taken with the circuit operating as a buck
switching regulator with all components mounted on
a PC board to simulate the junction temperature
under actual operating conditions. This curve can
be used for a quick check for the approximate
junction temperature for various conditions, but be
aware that there are many factors that can affect
the junction temperature. When load currents
higher than 2A are used, double sided or multilayer
PC boards with large copper areas and/or airflow
might be needed, especially for high ambient
temperatures and high output voltages.
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 thickness,
single or double-sided, multilayer 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.
Marking Information
(1) TO263-5L
( Top view )
Output Type:
1501: ADJ
1501-33: 3.3V
1501-50: 5.0V
1501-12: 12V
(2) TO220-5L
( Top view )
Output Type:
1501: ADJ
1501-33: 3.3V
1501-50: 5.0V
1501-12: 12V
AC
1501-XX
YY WW X X
Logo
Blank: normal
L: Lead Free Package
ID code
Xth week: 01~52
Year: "01" = 2001
"02" = 2002
AC
1501-XX
YY WW X X
Logo
Blank: normal
L: Lead Free Package
ID code
Xth week: 01~52
Year: "01" = 2001
"02" = 2002
~
~
Anachip Corp.
www.anachip.com.tw
8/11
Rev.A7 Feb. 10, 2004
ANACHIP [ ANACHIP CORP ]
