Application Information (continues)
Thermal resistance consists of two main elements, Θjc
(junction to case) and Θca (case to ambient). Using the
power SOP-8 reduces Θca, the total thermal
resistance, Θja (junction to ambient) is the limiting
factor in calculating the maximum power dissipation
capability of the device. Typically, the power SOP-8
have a Θjc of 20oC/W dramatically , this is significantly
lower than the standard SOP-8 which is typically
75oC/W. Θca is reduced because pin 5~8 can be
soldered directly to a ground plane which significantly
reduces the case to sink and sink to ambient thermal
resistance.
Power Dissipation
From under curves, the minimum area of copper
necessary for the par to operate safely can be
determined. The maximum allowable temperature rise
must be calculated to determine operation along
which curve.
TS39100/1/2/3
8-10
2004/06 rev. E
TSC [ TAIWAN SEMICONDUCTOR COMPANY, LTD ]
