Solution 3:

(i) To find the time constant to charge a 10 pF capacitor :

t = CR = 10x10^-12 x 50x10^3 = 0.5 uSec

(ii) To find the rise time for the device

tr = 3 x t = 1.5 uSec

(iii) To find the time constant to discharge a 10 pF capacitor :

t = CL/[ K( Vdd - Vt )]

= 10 x 10^-12/ [ (30/0.8)^-6 . ( 3.3 - 0.8 )]

= 0.106 µS

 

(iv) The fall time for the device ;

tf = 3 x t = 0.32 µS

 

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