A BiCMOS Darlington is shown in Fig. 11.51. Neglecting frequency effects, calculate the equivalent input noise voltage and current generators for this circuit, assuming that the dc value of V_iis adjusted for I_C1= 1 mA. Device data is μ_n C_ox= 60 µA/V², V_t= 0.7 V, λ = 0, γ = 0, W = 100 µm, L = 1 µm for the MOSFET and I_S= 10^ˆ’16A, V_A= ˆž, β = 100, r_b= 100 for the bipolar transistor. Use SPICE to check your calculation. Then add C_gs= 150 fF, C_sb= 50 fF for the MOSFET and C_μ= 50 fF, f_T= 10 GHz for the bipolar transistor and use SPICE to determine the frequency where the spectral density of the equivalent input noise voltage generator vÌ…²_ihas doubled. Also use SPICE to determine the equivalent input noise current spectral density at that frequency.

Fig. 11.51:

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5 V 2 ΚΩ R3 2 k2 M4 V; 100 2 R2 300 2 R1