ee 359 electronic circuits march 3, 2005 0 multistage amplifiers two stage cmos opamp bipolar opamp...

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March 3, 2005 1 EE 359 Electronic Circuits Multistage Amplifiers Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

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Page 1: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20051

EE 359 Electronic Circuits

Multistage AmplifiersMultistage Amplifiers

Two Stage CMOS OpAMP

Bipolar OpAmp

SPICE

Page 2: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20052

EE 359 Electronic Circuits

HW #5

• 7.10, 7.21, 7.71, 7.88

Due Tuesday

Page 3: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20053

EE 359 Electronic Circuits

Why Multistage?

• Practical transistor amplifiers consist of a number of stages connected in cascade.

• First stage typically high input impedance, & CMMR

• Middle stages amplification

• Last stage, low output impedance

Page 4: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20054

EE 359 Electronic Circuits

Two stage CMOS

Q8,Q5:current mirrors

Page 5: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20055

EE 359 Electronic Circuits

Differential Input

013

313 ||||

1

2rr

g

vgv O

m

idmg

Usually the leakage resistances are much larger than 1/g_m3

3

13 2 m

midg g

gvv

Page 6: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20056

EE 359 Electronic Circuits

Differential Gain

Page 7: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20057

EE 359 Electronic Circuits

Differential Input

22

2

23

41

234

idm

id

m

mmo

idmgmo

vg

v

g

ggi

vgvgi

Page 8: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20058

EE 359 Electronic Circuits

• vG2=0, vG1=vid

2/2

1

||

0

04020

omd

momid

d

ArgA

rrgRGv

vA

Page 9: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 20059

EE 359 Electronic Circuits

Equivalent Circuit MOSFET Opamp

Page 10: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200510

EE 359 Electronic Circuits

Bias Circuit for Opamp

• Bias current independent of Supply Voltage and MOSFET threshold volage

• Q_12, Q_13 deliberately mismatched, Q_12 4x wider

Page 11: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200511

EE 359 Electronic Circuits

Bipolar Opamp

Page 12: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200512

EE 359 Electronic CircuitsBipolar Opamp

Page 13: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200513

EE 359 Electronic Circuits

Small Signal Analysis

• Input and output Impedances

Page 14: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200514

EE 359 Electronic Circuits

Gain of Second Stage

Page 15: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200515

EE 359 Electronic Circuits

Last stage

Page 16: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200516

EE 359 Electronic Circuits

Small Signal Model

Page 17: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200517

EE 359 Electronic CircuitsFrequency Response

Page 18: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200518

EE 359 Electronic Circuits Spice Simulation

Page 19: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200519

EE 359 Electronic Circuits

Opamp Transfer Function

Page 20: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200520

EE 359 Electronic Circuits

Differential Gain

Page 21: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200521

EE 359 Electronic Circuits

Frequency Response• Adjust frequency resonse by adding resistor in Q4

Page 22: EE 359 Electronic Circuits March 3, 2005 0 Multistage Amplifiers Two Stage CMOS OpAMP Bipolar OpAmp SPICE

March 3, 200522

EE 359 Electronic Circuits

Common Mode Rejection Ratio