(a) For the op amp in Fig. 12.2, assume the CM and DM load capacitances are C_Lc= C_Ld= 2 pF. Calculate the frequencies at which |a_dm(jω) | = 1 and |a_cmc(jω) | = 1, ignoring other capacitors. Use |V_ov| = 0.25 V for all transistors, V_tn= ˆ’V_tp= 0.6 V, I_D5= 200 µA,V_An= 20 V, |V_Ap| = 25 V, and γ = 0.

Figure 12.2:

(b) Calculate the unity-gain frequencies in part (a) if C_Lc = 2 pF and C_Ld = 4 pF.

(c) The unity-gain frequency for the CMC gain can be made equal to the DM unity-gain frequency in part (b) by splitting M₅ as shown in Fig. 12.15. How should the 200 µA current be split between M₅₁ and M₅₂? AssumeV_ov51 = V_ov52 = 0.25 V.

Figure 12.15:

Transcribed Image Text:

VDD VBIAS M4 Mз Vo2 Vo1 Vi2 M2 M1 V;1 o Vemc M5 сте -Vss SS VDD VBIAS M4 Мз Vo2 Vo1 Vi2 M2 M1 Vi1 Vвв2 oV. V me M52 сте M51 -Vss