Datasheet

Application information TS982
14/21 Doc ID 9557 Rev 7
3 Application information
3.1 Exposed-pad package description
The dual operational amplifier TS982 is housed in an SO-8 exposed-pad plastic package.
As shown in Figure 40, the die is mounted and glued on a lead frame. This lead frame is
exposed as a thermal pad on the underside of the package. The thermal contact is direct
with the die and therefore, offers an excellent thermal performance in comparison with the
common SO packages. The thermal contact between the die and the exposed-pad is
characterized using the parameter R
thjc
.
Figure 40. Exposed-pad plastic package
As 90% of the heat is removed through the pad, the thermal dissipation of the circuit is
directly linked to the copper area soldered to the pad. In other words, the R
thja
depends on
the copper area and the number of layers of the printed circuit board under the pad.
Figure 41. TS982 test board layout - 6 cm
2
of copper topside
3.2 Exposed-pad electrical connection
In the SO-8 exposed-pad package, the silicon die is mounted on the thermal pad (see
Figure 40). The silicon substrate is not directly connected to the pad because of the glue.
Therefore, the copper area of the exposed-pad must be connected to the substrate voltage
(V
CC
-
) pin 4.