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Differential Amplifiers. Prof. Paul Hasler. Differential Transistor Pairs. MOSFET Diff-Pair. BJT Diff-Pair. Differential Transistor Pairs. MOSFET Diff-Pair. BJT Diff-Pair. The bottom transistor (the one with I bias ) sets the total current. Differential Transistor Pairs. MOSFET Diff-Pair.
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Differential Amplifiers Prof. Paul Hasler
Differential Transistor Pairs MOSFET Diff-Pair BJT Diff-Pair
Differential Transistor Pairs MOSFET Diff-Pair BJT Diff-Pair The bottom transistor (the one with Ibias) sets the total current
Differential Transistor Pairs MOSFET Diff-Pair BJT Diff-Pair The bottom transistor (the one with Ibias) sets the total current The upper two transistors compete for a fraction of this current
Analysis of Diff-Pair Source of Common-Mode Gain
Differential Pair Currents 3 Iout- Iout+ 2.5 2 (nA) 1.5 Output current 1 0.5 0 -0. 4 -0. 3 -0. 2 -0. 1 0 0.1 0.2 0.3 0.4 Differential input voltage (V)
BJT Differential Pair Analysis + - Iout Iout V1 V2 Vb GND
BJT Differential Amplifier + - Iout Iout V1 V2 Vb GND
Vdd Vdd Iout Vout BJT Differential Amplifier V1 V2 Vb GND
Vdd Vdd Iout Vout BJT Differential Amplifier Fixed output voltage: Current output Zero output current: Voltage output V1 V2 Vb GND
Wide-Output Range Differential Amplifier Simple differential amplifer "Vmin" effect
Simple differential amplifer "Vmin" effect Wide-Output Range Differential Amplifier Wide-output range amplifier
Simple differential amplifer "Vmin" effect Wide-Output Range Differential Amplifier Wide-output range amplifier
A Unity-Gain Follower Amp Gain = Av Av Solving: Vout = Vin 1 + Av A more ideal Follower / Buffer Circuit
A Unity-Gain Follower Amp Gain = Av Solving: Vout~ Vin
A Unity-Gain Follower Amp Gain = Av Solving: Vout ~ Vin
Differential Pairs / Amplifiers • Differential Transistor Pairs • Differential Amplifiers • Unity-Gain Amplifiers