Fundamentals-of-Microelectronics-Behzad-Razavi.pdf

26 in arriving at eq 1149 for the of transistors we

Info icon This preview shows pages 617–621. Sign up to view the full content.

View Full Document Right Arrow Icon
26. In arriving at Eq. (11.49) for the of transistors, we neglected and . Repeat the derivation without this approximation.
Image of page 617

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
BR Wiley/Razavi/ Fundamentals of Microelectronics [Razavi.cls v. 2006] June 30, 2007 at 13:42 593 (1) Sec. 11.10 Chapter Summary 593 M 1 V DD C F in C Figure 11.72 Q 1 R V CC C V b C 1 in C Figure 11.73 R V 1 Q C CC out V in V R B C F Figure 11.74 R V in V Q 1 CC C R B Q C F out V 2 Figure 11.75 27. It can be shown that, if the minority carriers injected by the emitter into the base take seconds to cross the base region, then . (a) Writing , assuming that is independent of the bias current, and using Eq. (11.49), derive an expression for the of bipolar transistors in terms of the collector bias current. (b) Sketch as a function of . 28. It can be shown that for a MOSFET operating in saturation. Using Eq.
Image of page 618
BR Wiley/Razavi/ Fundamentals of Microelectronics [Razavi.cls v. 2006] June 30, 2007 at 13:42 594 (1) 594 Chap. 11 Frequency Response V Q 2 b1 out I 1 V CC V in V Q 1 V CC Q V 3 b3 V in out C L V V Q 1 CC Q 2 V in out C L V V Q 1 CC Q 2 R B (c) (a) (b) Figure 11.76 V V V out V DD M M 2 1 in b V V V out V DD M M 2 1 in b M 2 V DD R E M V V out 1 R in V S b1 (c) (a) (b) Figure 11.77 (11.49), prove that (11.180) Note that increases with the overdrive voltage. 29. Having solved Problem 28 successfully, a student attempts a different substitution for : , arriving at (11.181) This result suggests that decreases as the overdrive voltage increases! Explain this apparent discrepancy between Eqs. (11.180) and (11.181). 30. Using Eq. (11.49) and the results of Problems 28 and 29, plot the of a MOSFET (a) as a function of for a constant , (b) as a function of for a constant . Assume remains constant in both cases. 31. Using Eq. (11.49) and the results of Problems 28 and 29, plot the of a MOSFET (a) as a function of for a constant , (b) as a function of for a constant . Assume remains constant in both cases. 32. Using Eq. (11.49) and the results of Problems 28 and 29, plot the of a MOSFET (a) as a function of for a constant , (b) as a function of for a constant . Assume remains constant in both cases. 33. In order to lower channel-length modulation in a MOSFET, we double the device length. (a) How should the device width be adjusted to maintain the same overdrive voltage and the same drain current? (b) How do these changes affect the of the transistor?
Image of page 619

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
BR Wiley/Razavi/ Fundamentals of Microelectronics [Razavi.cls v. 2006] June 30, 2007 at 13:42 595 (1) Sec. 11.10 Chapter Summary 595 34. We wish to halve the overdrive voltage of a transistor so as to provide a greater voltage head- room in a circuit. Determine the change in the if (a) is constant and is increased, or (b) is constant and is decreased. Assume is constant. 35. Using Miller’s theorem, determine the input and output poles of the CE and CS stages de- picted in Fig. 11.29(a) while including the output impedance of the transistors. 36. The common-emitter stage of Fig. 11.78 employs a current-source load to achieve a high gain V in V 1 Q CC R S out V Figure 11.78 (at low frequencies). Assuming and using Miller’s theorem, determine the input and output poles and hence the transfer function of the circuit.
Image of page 620
Image of page 621
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern