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 />
MOS TRANSISTOR OPERATED AS A PSEUDO-RESISTOR<br />
[11,12,13,6]<br />
Consequence <strong>of</strong> basic property I D = F(V S ) - F(V D ):<br />
CSEM, E. Vittoz, 2003<br />
page 16<br />
• Networks <strong>of</strong> transistors with same gate voltage are<br />
• l<strong>in</strong>ear with respect to currents<br />
• thus equiv. for currents to a resistive prototype, with Gi =1/Ri ~ISi • ground <strong>in</strong> res. prototype correspond to saturated transistors.<br />
• example <strong>of</strong> application: current-mode l<strong>in</strong>ear attenuator (e.g. R-2R).<br />
• In <strong>weak</strong> <strong><strong>in</strong>version</strong>:<br />
• l<strong>in</strong>earity <strong>of</strong> currents even for different gate voltages<br />
with G i = 1/R i ~ I Si exp V Gi<br />
nU T