EE 140 ANALOG INTEGRATED CIRCUITS SPRING 2009 PROBLEM SET 2 Issued Tuesday Feb 3 2009 Due Tuesday Feb 10 2009 6 00 p m in the EE 140 homework box in 240 Cory 1 Use inspection analysis to write expressions for the input resistance Ri output resistance Ro and gain vo vS for each of the amplifiers below The expressions should be in terms of the given elements and parameters of the small signal equivalent circuits i e gm rp r etc for the transistors used For each circuit assume that all capacitors shown have infinite values c a b d Fig PS2 1 2 Calculate numerical values for the input resistance Ri output resistance Ro gain vo vS and maximum amplitude of the signal source that still provides linear operation for the circuit in Fig PS2 1 d if R1 20k R2 62k RE 3 9k Rc 8 2k and VCC 12V Use 75 and an Early voltage VA 60V 3 Determine expressions for the small signal input resistance output resistance and gain for each of the circuits in Razavi Fig 3 67 except for b Use inspection analysis where possible but resort to the full small signal model if you deem it necessary EE 140 ANALOG INTEGRATED CIRCUITS SPRING 2009 4 For the Darlington emitter follower of Fig PS2 2 a Determine the dc collector currents in Q1 and Q2 and then the small signal input resistance and voltage gain Neglect r rb and ro and assume that VBE on 0 7V 200 VT 26mV 300k Use inspection analysis wherever possible b Determine the 3dB corner frequency fH of the gain using open circuit time constant methods Assume VBE on 0 7V 200 VT 26mV 300k fT 500MHz at IC 1mA C 0 4pF Cje 2pF CCS 1pF and neglect r rb and ro Note use the DC operating point found in a and assume zero source impedance VCC 10V Q1 Q2 vi 1 k 5V 50 Fig PS2 2 vo
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