OPA357 Datasheet, PDF (18/23 Pages) Burr-Brown (TI) – 250MHz, Rail-to-Rail I/O, CMOS Operational Amplifier with Shutdown

OPA357
OPA2357
SBOS235C − MARCH 2002− REVISED MAY 2004
5. Connect all holes, including those within the thermal pad
area and outside the pad area, to the internal ground plane
or other internal copper plane for single-supply
applications, and to V− for split-supply applications.
6. When laying out these holes, do not use the typical web
or spoke via connection methodology, as shown in
Figure 12. Web connections have a high thermal
resistance connection that is useful for slowing the heat
transfer during soldering operations. This makes soldering
the vias that have ground plane connections easier.
However, in this application, low thermal resistance is
desired for the most efficient heat transfer. Therefore, the
holes under the PowerPAD package should make their
connection to the internal ground plane with a complete
connection around the entire circumference of the
plated-through hole.
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7. The top-side solder mask should leave the pad
connections and the thermal pad area exposed. The
thermal pad area should leave the 13 mil holes exposed.
The larger holes outside the thermal pad area may be
covered with solder mask.
8. Apply solder paste to the exposed thermal pad area and
all of the package terminals.
9. With these preparatory steps in place, the PowerPAD IC
is simply placed in position and run through the solder
reflow operation as any standard surface-mount
component. This results in a part that is properly installed.
For detailed information on the PowerPAD package
including thermal modeling considerations and repair
procedures, please see Technical Brief SLMA002,
PowerPAD Thermally Enhanced Package, located at
www.ti.com.
Solid Via
RECOMMENDED
Web or Spoke Via
NOT RECOMMENDED
(due to poor heat conduction)
Figure 12. Internal ESD Protection
18