III. Gm-C Filtering - Epublications - Université de Limoges
III. Gm-C Filtering - Epublications - Université de Limoges
III. Gm-C Filtering - Epublications - Université de Limoges
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<strong>de</strong>picts this Rds resistance versus the drain current. As it may be found in the literature, the<br />
smaller the gate length L, the smaller the drain-source resistance since:<br />
LU a<br />
R ds = , (<strong>III</strong>.71)<br />
I d<br />
where Ua is a factor <strong>de</strong>pending on channel-length modulation.<br />
Figure 96. Drain-source resistance versus drain current<br />
As far as intrinsic noise and linearity of CMOS technologies are concerned, it is very<br />
difficult to compare one to another. In<strong>de</strong>ed, it strongly <strong>de</strong>pends on the mo<strong>de</strong>ling and its<br />
accuracy. Comparing technologies from different foun<strong>de</strong>rs may lead to misinterpretations.<br />
An important point in comparing technologies is their ability to support high supply<br />
voltages by means of thick oxi<strong>de</strong> transistors. Since the RF filter should be able to handle the<br />
LNA output swing, a high enough supply voltage is required. In<strong>de</strong>ed a 1.2V supply in 65nm<br />
CMOS would not be sufficient to handle a large swing without distortions. Minimum gate<br />
lengths and supply voltages of the various studied technologies are summarized in Table 6.<br />
CMOS technology<br />
Table 6. CMOS technologies comparison<br />
Name C14 C13 C90 C65 C45<br />
Provi<strong>de</strong>r NXP Jazz TSMC TSMC TSMC<br />
oxi<strong>de</strong> type thin thick thin thick thin thick thin thick thin thick<br />
Lmin (µm) 0,16 0,322 0,12 0,36 0.1 0.28 0,06 0,28 0,04 0,27<br />
Supply (V) 1,8 3,6 1,2 3,3 1.2 2.5 1,2 2,5 1.1 2,5<br />
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