This document discusses MOSFET amplifiers and includes the following topics: - Load line and Q-point analysis for different MOSFET biasing methods including feedback resistor biasing and voltage divider biasing. - Analysis of common-source, common-drain, and common-gate MOSFET amplifier configurations using hybrid-pi equivalent circuits. - MOSFET differential amplifier and its common-mode rejection ratio. - Multistage amplifiers such as cascade and cascode amplifiers.

1. ELECTRONIC CIRCUIT(21EC302)
•MOSFET Amplifiers
• Session-1
• (UNIT-2)
K.Sangeethalakshmi
• AP/ECE

2. UNIT-II
MOSFET AMPLIFIERS
Syllabus
• Load line, Q-point
• Biasing methods for MOSFET
• Analysis of CS, CD and CG MOSFET amplifiers using hybrid-pi equivalent
circuits
• MOSFET Differential amplifier – CMRR
• Multistage Amplifiers - Cascade amplifier, Cascode amplifier.

3. TOPICS TO BE DISCUSSED……
• Intoduction to Amplifier
• Load line, Q-point
• Biasing methods for MOSFET

4. AMPLIFIER

5. WHY MOSFET ??
• BJT FET
• Current controlled device voltage controlled device
• Bipolar Unipolar
• High voltage gain Low voltage gain
• Low Input Resistance High Input Resistance
• High output Resistance Low output Resistance
• High Power consumption Low Power consumption
• High Noise Less Noise

6. LOADLINE, Q-POINT IN DIFFERENT BIASING METHODS
1. BIASING WITH FEEDBACK RESISTOR

7. LOADLINE, Q-POINT IN DIFFERENT BIASING
METHODS
1. BIASING WITH FEEDBACK RESISTOR

8. LOADLINE, Q-POINT IN DIFFERENT BIASING METHODS
2. VOLTAGE DIVIDER BIASING

9. SMALL SIGNAL
HYBRID 𝝅 𝐞𝐪𝐮𝐢𝐯𝐚𝐥𝐞𝐧𝐭 𝐜𝐢𝐫𝐜𝐮𝐢𝐭 𝐨𝐟 𝐌𝐎𝐒𝐅𝐄𝐓

10. SMALL SIGNAL 𝐏𝐚𝐫𝐚𝐦𝐞𝐭𝐞𝐫𝐬 𝐨𝐟 𝐌𝐎𝑺𝐅𝐄𝐓
1.Transconductance(gm)
• gm =
𝜕𝑖𝐷
𝜕𝑣𝐺𝑆
• =
𝜕
𝜕𝑣𝐺𝑆
{Kn (VGS-VTN)2 }
• = 2Kn (VGS-VTN)
gm = 2Kn (VGS-VT)= 2 𝐾𝑛𝐼𝐷𝑄

11. 2. Output Resistance(ro)
• ro = [
𝜕𝑖𝐷
𝜕𝑣𝐷𝑆
]-1
=
𝜕
𝜕𝑣𝐷𝑆
{Kn (VGS-VTN)2 (1 + λ VDS)}-1
= {Kn (VGS-VTN)2 (λ)}-1
ro = [ λ IDQ ]-1