Analog CMOS Integrated Circuit Design Opamp Design References

Analog CMOS Integrated Circuit Design Opamp Design References: “Analog Integrated Circuit Design” by D. Johns and K. Martin and “Design of Analog CMOS Integrated Circuits” by B. Razavi All figures in this set of slides are taken from the above books Dr. Jawdat Abu-Taha Department of Electrical and Computer Engineering Islamic University of Gaza jtaha@iugaza. edu. ps 1

General Considerations • Gain • Small-signal bandwidth • Large-signal performance • Output swing • Input common-mode range • Linearity • Noise/offset • Supply rejection 2

One-Stage Op Amps 3

One-Stage Op Amp in Unity Gain Configuration 4

Cascode Op Amps 5

Unity Gain One Stage Cascode 6

Folded Cascode Op Amps EECE 488 Set 7 - Opamp Design 7

Folded Cascode Stages 8

Folded Cascode (cont. ) 9

Folded Cascode (cont. ) 10

Telescopic versus Folded Cascode 11

Example Folded-Cascode Op Amp 12

Single-Ended Output Cascode Op Amps 13

Triple Cascode 14

Output Impedance Enhancement 15

Gain Boosting in Cascode Stage 16

Differential Gain Boosting SM EECE 488 Set 7 - Opamp Design 17

Differential Gain Boosting SM EECE 488 Set 7 - Opamp Design 18

Differential Gain Boosting SM EECE 488 Set 7 - Opamp Design 19

Two-Stage Op Amps SM EECE 488 Set 7 - Opamp Design 20

Single-Ended Output Two-Stage Op Amp SM EECE 488 Set 7 - Opamp Design 21

Two-Stage CMOS Opamp

Two-Stage CMOS Opamp Example 23

Gain of the Opamp 24

Gain of the Opamp 25

Frequency Response 26

Frequency Response 27

Frequency Response 28

Frequency Response 29

Slew Rate 30

Slew Rate 31

Slew Rate 32

Systematic Offset Voltage 33

Systematic Offset Voltage 34

N-Channel versus P-Channel Input Stage 35

Feedback and Opamp Compensation 36

Stable and Unstable Systems 37

Time-domain response of a feedback system 38

One-pole system 39

Multi-pole system 40

Phase Margin 41

Phase Margin 42

Phase Margin (Cont. ) 43

Phase Margin (Cont. ) 44

Phase Margin (Cont. ) 45

Frequency Compensation 46

Telescopic Opamp (single-ended) -example 47

Compensation (Cont. ) • Assume we need a phase margin of 45 o (usually inadequate) and other non-dominant poles are at high frequency. 48

Compensation of a two-stage opamp 49

Compensating Two-Stage Opamps 50

Compensating Two-Stage Opamps 51

Compensating Two-Stage Opamps 52

Design Procedure 53

Design Procedure 54

Design Procedure 55

Process and Temperature Independence 56

Process and Temperature Independence 57

Process and Temperature Independence 58

Stable Transconductance Biasing 59

Stable Transconductance Biasing 60