Unformatted text preview: s smaller, resulting in less inversion. As a result, incremental voltage produces less incremental inversion charge, and the current does not
increase at much. When the drain voltage VDS is such that the difference between the gate and the drain voltage is equal to the threshold voltage, the incremental inversion charge/conductance becomes zero. Above this drain voltage (VDS(sat)), the drain current then becomes constant. Here we assume a long channel approximation, which means that the inversion charge region (L’) is still almost equal to L, the channel length. I V curve of drain current vs. drain source voltage for various gate bias. The higher the gate bias is over the threshold voltage, the larger the drain current. Note that from VG – VDS(sat) = VT, we have VDS(sat) = VG – VT. (a) for the reason described above. Derivation of the drain current vs. drain voltage in the Linear regime. Note that Qn’ is the inversion charge per unit area, and Cox is the oxide capacitance per unit area. ID vs. VDS in the Non Saturation regime. The derivation is in the book, Section 17.2.2. Note the quadratic dependence of ID vs. VDS. Substituting VDS(sat) for...
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This note was uploaded on 04/01/2014 for the course ECE 103 taught by Professor Wang during the Winter '08 term at UCSD.
 Winter '08
 WANG

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