ch13.6.htm

介绍asci设计的一本书

	 1.31</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131662">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131664">
 </A>
<SPAN CLASS="TableHeads">
Temperature/&#176;C</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131666">
 </A>
<SPAN CLASS="TableHeads">
4.5V</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131668">
 </A>
<SPAN CLASS="TableHeads">
4.75V</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131670">
 </A>
<SPAN CLASS="TableHeads">
5.00V</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131672">
 </A>
<SPAN CLASS="TableHeads">
5.25V</SPAN>
</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131674">
 </A>
<SPAN CLASS="TableHeads">
5.50V</SPAN>
</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131676">
 </A>
Nominal</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131678">
 </A>
	 1.0</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131680">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131682">
 </A>
&#8211;40</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131684">
 </A>
0.77</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131686">
 </A>
0.73</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131688">
 </A>
0.68</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131690">
 </A>
0.64</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131692">
 </A>
0.61</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131694">
 </A>
Fast</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131696">
 </A>
	 0.75</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131698">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131700">
 </A>
  0</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131702">
 </A>
1.00</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131704">
 </A>
0.93</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131706">
 </A>
0.87</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131708">
 </A>
0.82</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131710">
 </A>
0.78</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131712">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131714">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131716">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131718">
 </A>
 25</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131720">
 </A>
1.14</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131722">
 </A>
1.07</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131724">
 </A>
1.00</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131726">
 </A>
0.94</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131728">
 </A>
0.90</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131730">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131732">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131734">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131736">
 </A>
 85</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131738">
 </A>
1.50</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131740">
 </A>
1.40</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131742">
 </A>
1.33</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131744">
 </A>
1.26</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131746">
 </A>
1.20</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131748">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131750">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131752">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131754">
 </A>
100</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131756">
 </A>
1.60</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131758">
 </A>
1.49</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131760">
 </A>
1.41</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131762">
 </A>
1.34</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131764">
 </A>
1.28</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131766">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131768">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131770">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131772">
 </A>
125</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131774">
 </A>
1.76</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131776">
 </A>
1.65</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131778">
 </A>
1.56</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131780">
 </A>
1.47</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="Table">
<A NAME="pgfId=131782">
 </A>
1.41</P>
</TD>
</TR>
</TABLE>
</DIV>
<DIV>
<H2 CLASS="Heading2">
<A NAME="pgfId=65203">
 </A>
13.6.2&nbsp;Input-Slope Delay Model</H2>
<P CLASS="BodyAfterHead">
<A NAME="pgfId=68809">
 </A>
It is increasingly important for submicron technologies to account for the effects of the rise (and fall) time of the input waveforms to a logic cell. The nonlinear delay model described in this section was developed by Mike Misheloff at VLSI Technology and then at Compass. There are, however, no standards in this area&#8212;each ASIC company has its own, often proprietary, model.</P>
<P CLASS="Body">
<A NAME="pgfId=71279">
 </A>
We begin with some definitions:</P>
<UL>
<LI CLASS="BulletFirst">
<A NAME="pgfId=65224">
 </A>
<SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
0</SUB>
 is the time from the beginning of the input to beginning of the output.</LI>
<LI CLASS="BulletList">
<A NAME="pgfId=65207">
 </A>
<SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
1</SUB>
 is the time from the beginning of the input to the end of the output.</LI>
<LI CLASS="BulletLast">
<A NAME="pgfId=65209">
 </A>
<SPAN CLASS="EquationVariables">
I</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
 is the time from the beginning to the end of the input ramp.</LI>
</UL>
<P CLASS="Body">
<A NAME="pgfId=65208">
 </A>
In these definitions &#8220;beginning&#8221; and &#8220;end&#8221; refer to the projected intersections of the input waveform or the output waveform with <SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
DD</SUB>
 and <SPAN CLASS="EquationVariables">
V</SPAN>
<SUB CLASS="SubscriptVariable">
SS</SUB>
 as appropriate. Then we can calculate the delay, <SPAN CLASS="EquationVariables">
D</SPAN>
 (measured with 0.5 trip points at input and output),   and output ramp, <SPAN CLASS="EquationVariables">
O</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
, as follows:  </P>
<TABLE>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=131837">
 </A>
&nbsp;</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=131818">
 </A>
<SPAN CLASS="EquationVariables">
D</SPAN>
  =  (<SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
1</SUB>
 + <SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
0</SUB>
 &#8211;<SPAN CLASS="EquationVariables">
  I</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
)  /  2 </P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnNumber">
<A NAME="pgfId=131820">
 </A>
(13.12)</P>
</TD>
</TR>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=131839">
 </A>
and</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=131829">
 </A>
<SPAN CLASS="EquationVariables">
O</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
  =  <SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
1</SUB>
  &#8211;  <SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
0</SUB>
 .</P>
</TD>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnNumber">
<A NAME="pgfId=131831">
 </A>
(13.13)</P>
</TD>
</TR>
</TABLE>
<P CLASS="Body">
<A NAME="pgfId=65214">
 </A>
Experimentally we find that the times, <SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
0</SUB>
 and <SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
1</SUB>
, are accurately modeled by the following equations:  </P>
<TABLE>
<TR>
<TD ROWSPAN="1" COLSPAN="1">
<P CLASS="TableEqnLeft">
<A NAME="pgfId=132142">
 </A>
<SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="SubscriptVariable">
t</SUB>
<SUB CLASS="Subscript">
0</SUB>
  =  <SPAN CLASS="EquationVariables">
A</SPAN>
<SUB CLASS="Subscript">
0</SUB>
  +  <SPAN CLASS="EquationVariables">
D</SPAN>
<SUB CLASS="Subscript">
0</SUB>
  <SPAN CLASS="EquationVariables">
C</SPAN>
<SUB CLASS="SubscriptVariable">
L</SUB>
  +  <SPAN CLASS="EquationVariables">
B</SPAN>
   <SPAN CLASS="Symbol">
&#165;</SPAN>
  min (<SPAN CLASS="EquationVariables">
I</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
, <SPAN CLASS="EquationVariables">
C</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
)  +  <SPAN CLASS="EquationVariables">
Z</SPAN>
  <SPAN CLASS="Symbol">
&#165;</SPAN>
  max (0, <SPAN CLASS="EquationVariables">
I</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
  &#8211;  <SPAN CLASS="EquationVariables">
C</SPAN>
<SUB CLASS="SubscriptVariable">
R</SUB>
)</P>