Question

16.16. Explain qualitatively what happens to the VTC of CMOS inverter as the length of Mi or M2 is increased.

Answer 1

esut M ts Length e M, ts froreo.sed OFF and M ts that nH! Let's as assune in the ttede egfon yend YTRIMtopllrg cent (Condulingtn the atotonegfon oile seatsto theeor, cros As Vinneesses ON as be modeled fnvestas Can RON2 E nceasing L, ,, s eakened due to the fnuexse esut eguled to dop Vat to e an Foint woheee Vot = Vn +V ard M2 is at the edge sdusalian Theselaechasactetslic s shteto the ght and ft uot e steepex at the ain eglon usheve bot M, and ade In satuxalfon efon Length e M s fnoreased Lets OFF ond M, s ON sult Mis assome that H the ttode efon VRIMtost pullfrg curtent (Condutngin the tonegfon hile the tartode egion , opeaiy as ynd As Vinnexeases eatsto theeove, cos M2 1ssl t as be mode led nvestex Can By nceasing L, RoN becomes lastyes ; Mesult, touoe vake q I as Vouot compeale Cauaes a votage dp at the ostput M nto the satualfon th looex cuent ( This dtve and hence, loue Value . Theseloe, chaocertslic s left and Small signal gain utbe hghea to the