TS29100 Datasheet, PDF (7/8 Pages) Taiwan Semiconductor Company, Ltd – 1.0A Ultra Low Dropout Positive Voltage Regulator

Application Information (continues)
Power SOP-8 Thermal Characteristics
TS29101/2 series’ performance is its power SOP-8
package featuring half the thermal resistance of a
standard SOP-8 package. Lower thermal resistance
means more output current or higher input voltage for
a given package size.
Lower thermal resistance is achieved by connect the
four ground pins with the die attached pad to create a
single piece electrical and thermal conductor. This
concept have been used by MOSFET production for
years, proving very reliable and cost effective for the
user. As under:
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.
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 20^oC/W dramatically , this is significantly
lower than the standard SOP-8 which is typically
75^oC/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.
TS29100/1/2
7-7
2003/12 rev. A