Cascade Amplifier

• Multistage amplifier• Improved gain• Reduced bandwidth

Different Types• RC Coupled• Transformer Coupled• Direct coupled

Cascade AmplifierRC coupled amplifier Circuit diagram

Cascade AmplifierDesignGiven that,

Design of second stage:

Cascade Amplifier

• Design (continue…)

Cascade Amplifier

Design (continue..)

Cascade Amplifier

Design (Continue..)

Simulated Results:Designed values-

Standard values used for simulation

Cascade Amplifier

Simulated Results:DC bias conditions:Designed: Simulated:

Cascade Amplifier

Simulated Results:Cascade Amplifier

Simulated Results (Continue..)

Cascade Amplifier

Simulated Results (Continue..)Desired gainObtained gain

Scaling factor

New value of Rc,

Standard value

Cascade Amplifier

Cascade AmplifierSimulated Results (Continue..)

Design of first stage:

Cascade Amplifier

Design (continue..):

(Re design)

Cascade Amplifier

Simulated Results:Designed values:

Standard values used for simulation

Cascade Amplifier

Simulated Results (continue..):DC biased conditions:Designed Simulated

Cascade Amplifier

Cascade AmplifierSimulated Results (continue..):

Simulated Results (continue..):Cascade Amplifier

Simulated Results (Continue..)Desired gain Obtained gain

Scaling factor

Due to low load resistance (Ro1=Rc1 || Rin2) , scale RE1New value of Re,

Standard value

Cascade Amplifier

Simulated Results (Continue..)Cascade Amplifier

Cascade Amplifier

Combine the two stages…

Simulated Results of Two stage RC coupled Amplifier Cascade Amplifier

Cascade Amplifier

Cascade Amplifier

Simulated results:Scale RC and RE for undistorted output wave

and required gain AvScale Coupling capacitors for required lower

cutoff frequency fL

Cascade Amplifier

Thank You