THS7001_16 Datasheet, PDF (29/41 Pages) Texas Instruments – 70-MHz PROGRAMMABLE-GAIN AMPLIFIERS

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THS7001, THS7002
70ĆMHz PROGRAMMABLEĆGAIN AMPLIFIERS
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SLOS214C − OCTOBER 1998 − REVISED MARCH 2007
APPLICATION INFORMATION
general PowerPAD design considerations
Although there are many ways to properly heatsink this device, the following steps illustrate the recommended
approach.
THS7001
Thermal pad area (120 mils x 250 mils)
(3,05 mm x 6,35 mm)
with 8 vias
Via diameter = 13 mils (0,33 mm)
THS7002
Thermal pad area (120 mils x 300 mils)
(3,05 mm x 7,62 mm)
with 10 vias
Via diameter = 13 mils (0,33 mm)
Figure 68. PowerPAD PCB Etch and Via Pattern
1. Prepare the PCB with a top side etch pattern as shown in Figure 68. There should be etch for the leads as
well as etch for the thermal pad.
2. Place the thermal transfer holes in the area of the thermal pad. These holes should be 13 mils (0,33 mm)
in diameter. They are kept 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. This helps
dissipate the heat generated by the IC. These additional vias may be larger than the 13-mil (0,33 mm)
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 IC 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
thermal transfer holes exposed. The bottom-side solder mask should cover the thermal transfer 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 THS7001PWP/THS7002PWP 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.
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