AM1705_15 Datasheet, PDF (159/165 Pages) Texas Instruments – AM1705 ARM® Microprocessor

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AM1705
SPRS657E – FEBRUARY 2010 – REVISED JUNE 2014
8.2.1 Standoff Height
As illustrated in Figure 8-1, the standoff height specification for this device (between 0.050 mm and
0.150 mm) is measured from the seating plane established by the three lowest package pins to the lowest
point on the package body. Due to warpage, the lowest point on the package body is located in the center
of the package at the exposed thermal pad.
Using this definition of standoff height provides the correct result for determining the correct solder paste
thickness. According to TI's PowerPAD Thermally Enhanced Package Technical Brief (SLMA002), the
recommended range of solder paste thickness for this package is between 0.152 mm and 0.178 mm.
Standoff Height
Figure 8-1. Standoff Height Measurement on 176-pin PTP Package
8.2.2 PowerPAD™ PCB Footprint
In general, for proper thermal performance, the thermal pad under the package body should be as large
as possible. However, the soldermask opening for the PowerPAD™ should be sized to match the pad size
on the 176-pin PTP package; as illustrated in Figure 8-2.
Thermal Pad on Top Copper
should be as large as Possible.
Soldermask opening should be smaller and
match the size of the thermal pad on the package.
Figure 8-2. Soldermask Opening Should Match Size of Package Thermal Pad
8.3 Packaging Information
The following packaging information and addendum reflect the most current data available for the
designated device(s). This data is subject to change without notice and without revision of this document.
Copyright © 2010–2014, Texas Instruments Incorporated
Mechanical Packaging and Orderable Information 159
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