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<H1 CLASS="Heading1">
<A NAME="pgfId=19053">
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6.6 <A NAME="30210">
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Power Input</H1>
<P CLASS="BodyAfterHead">
<A NAME="pgfId=19054">
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The last item that we need to bring onto an FPGA is the power. We may need multiple VDD and GND power pads to reduce supply bounce or separate VDD pads for mixed-voltage supplies. We may also need to provide power for on-chip programming (in the case of antifuse or EPROM programming technology). The package type and number of pins will determine the number of power pins, which, in turn, affects the number of SSOs you can have in a design. </P>
<DIV>
<H2 CLASS="Heading2">
<A NAME="pgfId=78117">
</A>
6.6.1 <A NAME="40343">
</A>
Power Dissipation</H2>
<P CLASS="BodyAfterHead">
<A NAME="pgfId=78118">
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As a general rule a plastic package can dissipate about 1 W, and more expensive ceramic packages can dissipate up to about 2 W. <A HREF="CH06.6.htm#34932" CLASS="XRef">
Table 6.3</A>
shows the thermal characteristics of common packages. In a high-speed (high-power) design the ASIC power consumption may dictate your choice of packages. Actel provides a formula for calculating typical dynamic chip power consumption of their FPGAs. The formula for the ACT 2 and ACT 3 FPGAs are complex; therefore we shall use the simpler formula for the ACT 1 FPGAs as an example<SUP CLASS="Superscript">
<A HREF="#pgfId=85174" CLASS="footnote">
1</A>
</SUP>
: </P>
<TABLE>
<TR>
<TD ROWSPAN="1" COLSPAN="5">
<P CLASS="TableTitle">
<A NAME="pgfId=78125">
</A>
TABLE 6.3 <A NAME="34932">
</A>
Thermal characteristics of ASIC packages.</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableFirst">
<A NAME="pgfId=78135">
</A>
<SPAN CLASS="TableHeads">
Package</SPAN>
<SUP CLASS="Superscript">
<A HREF="#pgfId=84930" CLASS="footnote">
2</A>
</SUP>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableFirst">
<A NAME="pgfId=78137">
</A>
<SPAN CLASS="TableHeads">
Pin count</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableFirst">
<A NAME="pgfId=78139">
</A>
<SPAN CLASS="TableHeads">
Max. power P</SPAN>
<SUB CLASS="Subscript">
max</SUB>
<SPAN CLASS="TableHeads">
/W</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableFirst">
<A NAME="pgfId=78141">
</A>
<SPAN CLASS="TableHeads">
</SPAN>
<SPAN CLASS="Symbol">
q</SPAN>
<SUB CLASS="Subscript">
JA</SUB>
<SPAN CLASS="TableHeads">
/°CW</SPAN>
<SUP CLASS="Superscript">
–1</SUP>
</P>
<P CLASS="TableFirst">
<A NAME="pgfId=78459">
</A>
<SPAN CLASS="TableHeads">
(still air)</SPAN>
<SUP CLASS="Superscript">
<A HREF="#pgfId=78144" CLASS="footnote">
3</A>
,<A HREF="#pgfId=78478" CLASS="footnote">
4</A>
</SUP>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableFirst">
<A NAME="pgfId=78146">
</A>
<SPAN CLASS="Symbol">
q</SPAN>
<SUB CLASS="Subscript">
JA</SUB>
<SPAN CLASS="TableHeads">
/°CW</SPAN>
<SUP CLASS="Superscript">
–1</SUP>
</P>
<P CLASS="TableFirst">
<A NAME="pgfId=78150">
</A>
<SPAN CLASS="TableHeads">
(still air)</SPAN>
<SUP CLASS="Superscript">
<A HREF="#pgfId=78149" CLASS="footnote">
5</A>
</SUP>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78152">
</A>
CPGA</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78154">
</A>
84</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78156">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78158">
</A>
33</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78160">
</A>
32–38</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78162">
</A>
CPGA</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78164">
</A>
100</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78166">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78168">
</A>
35</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78170">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78172">
</A>
CPGA</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78174">
</A>
132</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78176">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78178">
</A>
30</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78180">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78185">
</A>
CPGA</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78187">
</A>
175</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78189">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78191">
</A>
25</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78193">
</A>
16</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78195">
</A>
CPGA</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78197">
</A>
207</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78199">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78201">
</A>
22</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78203">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78205">
</A>
CPGA</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78207">
</A>
257</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78209">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78211">
</A>
15</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78213">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78215">
</A>
CQFP</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78217">
</A>
84</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78219">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78221">
</A>
40</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78223">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78225">
</A>
CQFP</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78227">
</A>
172</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78229">
</A>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78231">
</A>
25</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78233">
</A>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78235">
</A>
PQFP</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78237">
</A>
100</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78239">
</A>
1.0</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78241">
</A>
55</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78243">
</A>
56–75</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78245">
</A>
PQFP</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78247">
</A>
160</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78249">
</A>
1.75</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78251">
</A>
33</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78253">
</A>
30–33</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78255">
</A>
PQFP</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78257">
</A>
208</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78259">
</A>
2.0</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=78261">
</A>
33</P>
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