useful_formulas

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 — useful_formulas [2015/05/06 20:21] (current)104.228.198.109 created 2015/05/06 20:21 created 2015/05/06 20:21 created Line 1: Line 1: + ====== Useful Formulas ====== + ---- + + ==== MOSFET Current Equations ==== + $I_D=\frac{1}{2}\mu C_{ox}\frac{W}{L}\left ( V_{GS}-V_T \right )^2$ + $I_D=\mu C_{ox}\frac{W}{L}\left [\left ( V_{GS}-V_T \right ) V_{DS}-\frac{1}{2}V_{DS}^{2} \right ]$ + ==== MOSFET Transconductance ==== + $g_m=\sqrt{2\mu C_{ox}\frac{W}{L}I_D}$ + $g_m=\frac{2I_D}{V_{GS}-V_T}$ + $g_m=\mu C_{ox}\frac{W}{L}\left ( V_{GS}-V_T \right )$ + ==== Small Signal Resistance ==== + $r_o=\frac{1}{\lambda I_D}$ + ==== Cascode Input Resistance ==== + $r_{in}=\left [ 1 + \left ( g_{m1} + g_{mb1} \right )r_{o1} \right ]r_{o2}+r_{o1}$ + $r_{in}\approx g_{m1}r_{o1}r_{o2}$