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(Solved): Question 3 3.1 An npn transistor is operating at a collector current of 1 mA at 350 K with h_(fe)=60 ...
Question 3
3.1 An npn transistor is operating at a collector current of 1 mA at 350 K with h_(fe)=60, a bandwidth f_(\beta )
=1MHz and a minority electron diffusion coefficient D_(n)=20c(m^(2))/(sec). Determine the following
design parameters for this transistor: (i) C_(\pi ), iif_(T),
(iii) the transistor base width, W and (iv) the minority electron lifetime in base region, \tau _(n).
3.2 An npn transistor at 300 K operating at collector current of 2 mA with an f_(T) of 60 MHz , low
frequency h_(fc)=50, and a collector capacitance of 8 pF . Calculate its short-circuit bandwidth and
its diffusion capacitance?
3.3 Consider a BJT operating at a collector current of 1.5 mA and a MOSFET of comparable size
having the following parameters: C_(ox)Zl=0.022pF,\mu =620c(m^(2))/(V)-sec, l=2.5\mu m, and V_(GS) -
V_(T)=3V. Roughly determine the ratio of the GBW of the BJT to that of the MOSFET assuming
comparable input capacitances of these devices.