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LDTC0520 / LDTC1020
PAGE 10
LDTC1020-00400-A Rev B
TYPICAL PERFORMANCE GRAPHS - WTC
Caution:
Do not exceed the Maximum Internal Power Dissipation of the FL or WTC.
Safe Operating Area (SOA) tools are provided online to make your design easier.
Exceeding the Maximum Internal Power Dissipation voids the warranty.
To determine if specifi c operating parameters fall within the SOA of the device, the maximum voltage drop across the
controller and the maximum current must be plotted on the SOA curves.
These values are used for the example SOA determination for a WTC:
Vs= 12 Volts
Vload = 5 Volts
ILoad = 1 Amp
Follow these steps:
1.
Determine the maximum voltage drop across the controller ,Vs-Vload, and mark on the X axis.
(12 Volts - 5 Volts = 7 Volts, Point A)
2.
Determine the maximum current through the controller and mark on the Y axis:
(1 Amp, Point B)
3.
Draw a horizontal line through Point B across the chart. (Line BB)
4.
Draw a vertical line from Point A to the maximum current line indicated by Line BB.
5.
Mark Vs on the X axis. (Point C)
6.
Draw the Load Line from where the vertical line from point A intersects Line BB down to Point C.
Refer to the chart shown below and note that the Load Line is in the Unsafe Operating Areas for use with no heatsink
(1) or the heatsink alone (2), but is within of the Safe Operating Area for use with heatsink and Fan (3).
An online tool for calculating your load line is at
http://www.teamwavelength.com/tools/calculator/soa/defaulttc.htm
.
25 C Case
A
B
BB
C
Proper heat dissipation from the WTC is critical to longevity of the LDTC. The heat spreader of the WTC3243
is positioned to use your chassis for heat dissipation. Be sure to add thermally conductive paste to all relevant
surfaces that need to dissipate heat.
