Datasheet

Mold Compound (Epoxy)
Leadframe Die Pad
Exposed at Base of the Package
Leadframe (Copper Alloy)
(a) DWP PowerPAD cross-section view
(b) DWD PowerPAD cross-section view
IC (Silicon)
Die Attach (Epoxy)
Board
External Heatspreader
Power Transistor
Chip
Die
Attach
Thermal
Paste
Die
Pad
WeborSpokeViaSolidVia
NOTRECOMMENDEDRECOMMENDED
OPA564
SBOS372E –OCTOBER 2008– REVISED JANUARY 2011 www.ti.com
Figure 49. Cross-Section Views
holes under the PowerPAD package should be
Bottom-Side PowerPAD Assembly Process
connected to the internal plane with a complete
1. The PowerPAD must be connected to the most connection around the entire circumference of the
negative supply of the device, V–. plated through-hole.
2. Prepare the PCB with a top side etch pattern, as 7. The top-side solder mask should leave exposed
shown in the attached thermal land pattern the terminals of the package and the thermal pad
mechanical drawing. There should be etch for the area. The thermal pad area should leave the
leads as well as etch for the thermal land. 13mil holes exposed. The larger 25mil holes
outside the thermal pad area should be covered
3. Place the recommended number of holes (or
with solder mask.
thermal vias) in the area of the thermal pad, as
seen in the attached thermal land pattern 8. Apply solder paste to the exposed thermal pad
mechanical drawing. These holes should be area and all of the package terminals.
13mils (.013in, or 330.2mm) in diameter. They are
9. With these preparatory steps completed, the
kept small so that solder wicking through the
PowerPAD IC is simply placed in position and run
holes is not a problem during reflow.
through the solder reflow operation as any
4. It is recommended, but not required, to place a standard surface-mount component. This
small number of the holes under the package and processing results in a part that is properly
outside the thermal pad area. These holes installed.
provide an additional heat path between the
For detailed information on the PowerPAD package
copper land and ground plane and are 25mils
including thermal modeling considerations and repair
(.025in, or 635mm) in diameter. They may be
procedures, see Technical Brief SLMA002,
larger because they are not in the area to be
PowerPAD Thermally Enhanced Package, available
soldered, so wicking is not a problem. This
at www.ti.com.
configuration is illustrated in the attached thermal
land pattern mechanical drawing.
5. Connect all holes, including those within the
thermal pad area and outside the pad area, to the
internal plane that is at the same voltage potential
as V–.
6. When connecting these holes to the internal
plane, do not use the typical web or spoke via
connection methodology (as Figure 50 shows).
Web connections have a high thermal resistance
connection that is useful for slowing the heat
transfer during soldering operations. This
configuration makes the soldering of vias that
have plane connections easier. However, in this
Figure 50. Via Connection Methods
application, low thermal resistance is desired for
the most efficient heat transfer. Therefore, the
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