1. Analog Quick Notes Ravi Dixit www.learnanalog.com

2. MOS Operation Modes Cutoff if V gs < V t then I ds = 0 Linear if V gs > V t & V ds < V gs – V t then Saturation If V gs > V t & V ds > V gs – V t then

3. Required Characteristics of Amplifier High Gain for bandwidth of operation Less power consumption Required linear input output transfer characteristic for less distortion Large output signal swing Less silicon area Noise generated by amplifier should be low Robust to Process, Supply & Temperature variations High input impedance (shouldnt load previous stage) Low output impedance (should efficiently drive next stage or load)

4. Single Stage Amplifier Common Source Common Drain ( Source Follower) Common Gate

5. Common Source Amplifier Voltage Amplifier Input Impedance : High( Infinity) Output Impedance : Moderate (~ R load ) Voltage Gain : Moderate (~ - g m * R load ) Current Gain : Infinity Bandwidth : low ( Gate source high effective capacitance due to miller effect )

6. Common Drain Amplifier Voltage Buffer Also known as Source Follower Input Impedance : High ( Infinity) Output Impedance : Moderate (~ R load ||1/g m ) Voltage Gain : ~ Unity (R load / (R load + 1/g m ) Current Gain : Infinity Bandwidth : High

7. Common Gate Amplifier Used as a Current Buffer or Voltage Amplifier Input Impedance : Low ( ~ 1/g m ) Output Impedance : Moderate (~ R load ) Voltage Gain : Moderate (~ g m * R load ) Current Gain : Unity Bandwidth : Moderate

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