Solution : Chapter - 18

Solution 1:

(i) To find VIL and Vo(IL) ;

VIL = VT + 1/K.RL

VIL = 0.8 + 1/(40x75) = 0.8003V

Vo(IL) = Vdd - [K(VIL - Vt)^2].RL/2

= 5 - [40.( 0.8003 - 0.8 )^2] x 75/2 = 4.999V

(ii) To find VIH and Vo(IH) ;

3K[(VIH - Vt)^2]/8 + (VIH - Vt)/2.RL - Vdd/RL = 0

3x40[( VIH - Vt)^2]/8 + (VIH - Vt)/2x75 - 5/75 = 0

15(VIH - Vt)^2 + 15(VIH - Vt) - 66.6 = 0

VIH - Vt= 1.665V ; VIH = 2.465 V

Vo(IH) = (VIH - Vt)/2 = 0.833V

(iii) To find VM:

(K/2).(VM^2) + [(1/RL) - K.Vt]VM + [(K/2).Vt^2 - Vdd/RL] = 0

20.VM^2 + [(1/75) - 40x0.8]VM + [( 20x(0.8)^2 - (5/75)] =0

20VM^2 - 18.67VM - 53.86 = 0

VM = 1.24V

(iv) To find VOH and VOL ;

VOH = Vdd = 5V

VOL = Vdd/[ K.RL ( Vdd - Vt ) + 1] = 5/[40x75(5 - 0.8) +1 ] = 0.367 V

 

Voltage Transfer Characteristics