OPA1632 Datasheet, PDF (8/12 Pages) Texas Instruments – High-Perfomance, Fully-Differential AUDIO OP AMP

OPA1632
SBOS286 − DECEMBER 2003
The PowerPAD package allows for both assembly and
thermal management in one manufacturing operation.
During the surface-mount solder operation (when the
leads are being soldered), the thermal pad can also be
soldered to a copper area underneath the package.
Through the use of thermal paths within this copper
area, heat can be conducted away from the package
into either a ground plane or other heat-dissipating
device.
PowerPAD PCB LAYOUT CONSIDERATIONS
1. Prepare the printed circuit board (PCB) with a
top-side etch pattern, as shown in Figure 4. There
should be etch for the leads as well as etch for the
thermal pad.
ÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓÓ ^{Single or Dual}
68mils x 70mils
(via diameter = 13mils)
Figure 4. PowerPAD PCB Etch and Via Pattern.
2. Place five holes in the area of the thermal pad.
These holes should be 13mils in diameter. Keep
them small so that solder wicking through the holes
is not a problem during reflow.
3. Additional vias may be placed anywhere along the
thermal plane outside of the thermal pad area.
These vias help dissipate the heat generated by the
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OPA1632 IC, and may be larger than the 13mil
diameter vias directly under the thermal pad. They
can be larger because they are not in the thermal
pad area to be soldered so that wicking is not a
problem.
4. Connect all holes to the internal ground plane.
5. When connecting these holes to the ground plane,
do not use the typical web or spoke via connection
methodology. Web connections have a high
thermal resistance connection that is useful for
slowing the heat transfer during soldering
operations. This makes the soldering of vias that
have plane connections easier. In this application,
however, low thermal resistance is desired for the
most efficient heat transfer. Therefore, the holes
under the OPA1632 PowerPAD package should
make their connection to the internal ground plane
with a complete connection around the entire
circumference of the plated-through hole.
6. The top-side solder mask should leave the terminals
of the package and the thermal pad area with its five
holes exposed. The bottom-side solder mask should
cover the five holes of the thermal pad area. This
prevents solder from being pulled away from the
thermal pad area during the reflow process.
7. Apply solder paste to the exposed thermal-pad
area and all of the IC terminals.
8. With these preparatory steps in place, the IC is
simply placed in position and runs through the
solder reflow operation as any standard
surface-mount component. This results in a part
that is properly installed.
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