D *9.106 In a particular design of the CMOS op amp of Fig. 9.37 the designer wishes to investigate the effects of increasing the W/L ratio of both Q1 and Q2 by a factor of 4. Assuming that all other parameters are kept unchanged, refer to Example 9.6 to help you answer the following questions:
(a) What change results in |VOV| and in gm of Q1 and Q2?
(b) What change results in the voltage gain of the input stage? In the overall voltage gain?
(c) What is the effect on the input offset voltages? (You might wish to refer to Section 9.4).
– |Vov| is reduced by a factor of 2 and gm increases by a factor of 20; (b) Both increase by a factor of 20; (c) increases by a factor 2 (except for Vos due to ΔVt).
1 Answer