The expression with gds0 is more accurate and should

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Unformatted text preview: noise (strong inversion) – Drain current (use gds0 not gm) γ = 2/3 for small fields (long L) can be 1-2 or even larger for short L • Since the expression with gm is convenient for input referred noise calculations, it is often used. The expression with gds0 is more accurate and should be used. The factor α captures the drop in gm for a short channel device. • Gate induced noise (142/242 topic) • Gate current (leakage shot noise) • No noise from ro (not physical resistor) • Extrinsic noise sources (drain/source/gate resistance) EECS 240 Lecture 5: Noise © 2006 A. M. Niknejad and B. Boser 15 FET Noise Model • The resistance of the substrate also generates thermal noise. In most circuits we will be concerned with the noise due to the channel an...
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