www.ti.com | TPS54810 |
SLVS420B − MARCH 2002 − R EVISED FEBRUARY 2005
LAYOUT CONSIDERATIONS FOR THERMAL PERFORMANCE
For operation at full rated load current, the analog ground plane must provide adequate heat dissipating area. A 3 inch by 3 inch plane of 1 ounce copper is recommended, though not mandatory, depending on ambient temperature and airflow. Most applications have larger areas of internal ground plane available, and the PowerPAD should be connected to the largest area available. Additional areas on the top or bottom layers also help dissipate heat, and
any area available should be used when 8 A or greater operation is desired. Connection from the exposes area of the PowerPAD to the analog ground plane layer should be made using 0.013 inch diameter vias to avoid solder wicking through the vias. Eight vias should be in the PowerPAD area with four additional vias located under the device package. The size of the vias under the package, but not in the exposed thermal pad area, can be increased to 0.018. Additional vias beyond the twelve recommended that enhance thermal performance should be included in areas not under the device package.
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| Minimum Recommended Thermal Vias: 8 x 0.013 Diameter Inside | |
| 8 PL Ø0.0130 | Powerpad Area 4 x 0.018 Diameter Under Device as Shown. | ||
| 4 PL | Ø0.0180 | Additional 0.018 Diameter Vias May Be Used if Top Side Analog Ground | |
| Area Is Extended. |
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Connect Pin 1 to Analog Ground Plane |
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in This Area for Optimum Performance | 0.06 0.0150 | |||
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| 0.0339 |
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| 0.0650 |
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| 0.0500 |
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0.3820 | 0.3478 | 0.0500 |
| 0.2090 |
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| 0.0500 | 0.0256 |
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| 0.0650 |
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| 0.0339 |
| Minimum Recommended Exposed |
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| 0.1700 | Copper Area for Powerpad. |
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| Stencils May Require 10 Percent | |
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Minimum Recommended Top | 0.1340 | Larger Area | ||
0.0630 |
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Side Analog Ground Area |
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| 0.0400 |
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Figure 11. Recommended Land Pattern for the 28−Pin PWP PowerPAD
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