1 (1066)

Prévia do material em texto

Step of 6 10.104P Refer to Figure 9.41 (c) in the textbook for the common drain- common gate amplifier circuit diagram. Draw the small signal equivalent circuit. Cgd + V₁ + - - + - RL Cgd Figure 1 Step 6 From the circuit in Figure 1, the input voltage is the sum of the gate to source voltage of the MOSFET 1 and gate to source voltage of the MOSFET 2. That is, The current flowing through the load is, Therefore, the output voltage is, Determine the ratio of output voltage to input voltage to get the voltage gain. 2 Thus, the mid- band voltage gain is, Step of Substitute 5 mA/V for and for to calculate the voltage gain AM 2 100 = 2 50 V/V Thus, the mid- band gain is, Step of The pole at the input, with a frequency by neglecting is, 1 Here, The gate to source capacitance, The gate to drain capacitance, Substitute 2 pF for and 0.1 pF for 2 1 = ) = 7.23 MHz Step 6 The pole at the input, with a frequency is, Here, The gate to drain capacitance, The load capacitance, The load resistance, Step Substitute 0.1 pF for pF for and for = 7.23 MHz Write the expression for the frequency at which the gain downs by 3 dB. + Substitute 7.23 MHz for and 7.23 MHz for for 1 1 I = I = Thus, the 3 dB frequency is.