GATE 2016 EC – Question 47

Electronic Devices · P-N Junction and Semiconductor Devices · 2 marks · Numerical answer

Consider an $n$-channel metal oxide semiconductor field effect transistor (MOSFET) with a gate-to-source voltage of 1.8 V. Assume that $\frac{W}{L} = 4$, $\mu_N C_{ox} = 70 \times 10^{-6}$ A V$^{-2}$, the threshold voltage is 0.3 V, and the channel length modulation parameter is 0.09 V$^{-1}$. In the saturation region, the drain conductance (in micro siemens) is ________

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Correct answer: 28 to 29

Explanation

The saturation current is $I_D = \frac{1}{2}\mu_N C_{ox}\frac{W}{L}(V_{GS} - V_T)^2 = \frac{1}{2}(70 \times 10^{-6})(4)(1.5)^2 = 315\ \mu$A. The drain conductance in saturation is $g_d = \lambda I_D = 0.09 \times 315\ \mu\text{A} = 28.35\ \mu$S.