A differential input stage is shown in Fig. 11.54.

(a) Neglecting flicker noise, calculate expressions for the equivalent input noise voltage and current generators at the base of Q₁. Use SPICE to check your result.

(b) Assuming the circuit has a dominant pole in its frequency response at 30 MHz and R_S = 50, calculate the total equivalent input and output noise voltages. Data: β = 100; r_b = 200 Ω.

Fig. 11.54:

 

Transcribed Image Text:

+10 V 20 k2 20 kQ Rs Q2 Q1 500 2 500 2 100 k2 -10 V