weak inversion in analog and digital circuits - Lund Institute of ...
weak inversion in analog and digital circuits - Lund Institute of ...
weak inversion in analog and digital circuits - Lund Institute of ...
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Weak <strong><strong>in</strong>version</strong><br />
EVOLUTION OF IC WITH SCALED-DOWN PROCESSES<br />
• Scal<strong>in</strong>g-down <strong>of</strong> process:<br />
• dimension scal<strong>in</strong>g by factor k<br />
• all voltages decreased by k, except U T :<br />
- <strong>analog</strong> <strong>circuits</strong>: V DSsat must be decreased by k, thus<br />
V DSsat<br />
2U T<br />
- <strong>digital</strong> <strong>circuits</strong>: V B decreased by k, thus<br />
VB -V<br />
IC<br />
⎛ T0<br />
on =<br />
⎝<br />
decreased by k<br />
2nUT • Weak <strong><strong>in</strong>version</strong> approached for constant temperature T.<br />
2<br />
µVDSsat • Transition frequency: fT = <strong>in</strong>creased by k<br />
2πL2 - <strong>weak</strong> <strong><strong>in</strong>version</strong> with L=100nm : fT >4 GHz<br />
⎛<br />
⎝<br />
CSEM, E. Vittoz, 2003<br />
⎛<br />
⎝ IC =<br />
2<br />
⎛<br />
⎝<br />
2<br />
decreased by k 2<br />
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