Operational Amplifiers with Single Ended Outputs

In the previous three chapters, the most important circuit building blocks utilized in analog integrated circuits (ICs) have been studied. Most analog ICs consist primarily of these basic circuits connected in such a way as to perform the desired function. Although the variety of standard and special-purpose custom ICs is almost limitless, a few standard circuits stand out as perhaps having the widest application in systems of various kinds. These include operational amplifiers, voltage...

7 A Analysis of the Frequency Response of the 741 Op

Up to this point the analysis of the frequency response of integrated circuits has been limited to fairly simple configurations. The reason for this is apparent in previous sections, where the large amount of calculation required to estimate the dominant pole of some simple circuits was illustrated. A complete frequency analysis by hand of a large integrated circuit is thus out of the question. However, a circuit designer often needs insight into the frequency response of large circuits such as...

R3

Therefore, the DM and CMFB loops As rrfOT or rcm t increases, Adm- work to reduce the closed-loop DM-to-CM cross gain. Again, the (1 + Tc effect here since 1 + Tcm 1. The analysis in this section shows how the closed-loop cross-gain terms for the feedback amplifier in Fig. 12.32a are affected by imbalances in the op amp and feedback network. In practice, the imbalances are usually caused by random mismatches between components, and the effect of such mismatches on circuit performance...

Eb

Figure 4.48 A circuit that increases AVEB by increasing l h and l Jh . Thus cascading two identical emitter followers doubles A Veb while only doubling the required die area. The effect of the offset in a band-gap reference can also be reduced by using offset cancellation. An example of offset cancellation in a CMOS band-gap reference with curvature correction in addition to an analysis of other high-order effects arising from finite Pf, Pf mismatch, (3f variation with temperature, nonzero base...

Example

Modify the single-ended two-stage op amp from the examples in Section 6.3.5 and Section 9.4.3 into a fully differential op amp. It will be used in the feedback circuit shown in Fig. 12.25, which represents the connections in a switched-capacitor circuit when one clock is high (assuming the switches are ideal). The capacitor values are Cs 2 pF, CF 5 pF, and CL 2 pF. Design for 1-V peak output swing and phase margins of 45 or greater in the DM and CMFB loops. Use VDD Vss 1.65 V, and design for a...

References

Modern Control Engineering, 2nd Edition. Prentice-Hall, Englewood Cliffs, NJ, 1990. 2. P. W. Tuinenga. SPICE A Guide to Circuit Simulation and Analysis using PSPICE, 3rd Edition. Prentice-Hall, Englewood Cliffs, NJ, 1995. 3. G. W. Roberts and A.S. Sedra. SPICE, 2nd Edition. Oxford Press, New York, 1997. 4. P. J. Hurst. Exact Simulation of Feedback Circuit Parameters, IEEE Trans, on Circuits and Systems, Vol. CAS-38, No. 11, pp. 1382-1389, November 1991. 5. P. J. Hurst and S.H....

A Q

Cmfb For Two Stage Opamp

Comparing 12.71 with 12.68 shows that AQ CX introduces an offset in Voc, making Voc differ from VCM when VCSBlAS Vcmc. If VCM was chosen to maximize the op-amp output swing, a shift in Voc will reduce the op-amp output swing. The magnitude of the charge transferred by each switch transistor increases with its width W since the gatechannel and overlap capacitances are proportional to W as shown in 1.187 and 2.45 , so a trade-off exists between low switch on-resistance and small charge transfer....

3

Common Emitter Amplifier Transfer Curve

Figure 4.16 a Common-emitter amplifier with active load, b Common-source amplifier with active load. Figure 4.17 a I-V characteristics of the input transistor. b I-V characteristic of the active load, c J-V characteristics with load characteristic superimposed, d dc transfer characteristic of common-emitter or common-source amplifier with current-mirror load. Figure 4.17 a I-V characteristics of the input transistor. b I-V characteristic of the active load, c J-V characteristics with load...