1 / 9

Finite Gain Effects in SC Circuits

Finite Gain Effects in SC Circuits. Gabor C Temes School of EECS Oregon State University Rev. 03/09/ 2013. Non-Idealities of an Op-Amp. DC offset voltage Finite dc gain Finite bandwidth Nonzero output impedance Noise. Model for Finite Gain. Model for Finite-Gain Effect.

belden
Download Presentation

Finite Gain Effects in SC Circuits

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Finite Gain Effects in SC Circuits Gabor C Temes School of EECS Oregon State University Rev. 03/09/2013

  2. Non-Idealities of an Op-Amp • DC offset voltage • Finite dc gain • Finite bandwidth • Nonzero output impedance • Noise 1/8

  3. Model for Finite Gain 2/8

  4. Model for Finite-Gain Effect • ∆Qi=Yi(Vi+-Vi-) • ∆Q is the charge flow in one clock period. • For Ao infinity, ∆Q1=Y1*Vin=-∆Q2=-Y2*Vo So, H(z) = -Y1/Y2 when Ao infinity • For finite Ao: ∆Q1=Y1(Vin+Vo/Ao) =-∆Q2=-Y2(Vo+Vo/Ao) H(z) = -Y1/(Y2+Y1/Ao+Y2/Ao) 3/8

  5. Finite Gain Model ∞ 4/8

  6. Time Domain Analysis q1(n) = C1[vin(n)-v-(n)]=q2(n) q2(n)=-C2[vo(n) - v-(n) - vo(n-1)+v-(n-1)] 5/8

  7. Finite D.C. Gain Effects Analysis C1vin(n) = -C2vo(n)+v-(n)[C1+C2]+C2vo[n-1] – C2v-(n-1) C1vin(n) = -C2[vo(n)-vo(n-1)] - [C1+C2)/A]vo(n)+(C2/A)vo(n-1) C1vin(n) =-C2(1+1/A)[vo(n)-vo(n-1)]+(C1/A)vo(n) (C1/A)vo(n) error is critical. It causes a phase error near dc C2(1+1/A)[vo(n)-vo(n-1)] error is negligible. 6/8

  8. Finite D.C. Gain Effects Analysis Φ (C1/A)vo(n) error causes a phase error near dc. (C1/A)vo error causes phase error near dc. 7/8

  9. Finite Gain Model vcmi vcmo vin vout ∞ 8/8

More Related