Embedded Systems Design Europe - May 2008 - (Page 30)

analog Delve deep into the mathematics of ﬁlters and their sensitivities to component variations, using tools such as Monte Carlo analysis to determine how much a ﬁlter’s transfer function will vary. Analyzing circuit sensitivity for analog circuit design BY MARK FORTUNATO ll circuits, analog or digital, have characteristics dependent on the values of their component parts. Invariably, these parts are nonideal in many ways. Even their most fundamental characteristics, for example a resistor’s resistance, will be at least slightly different from the speciﬁed value. These characteristics also can vary over time and environmental conditions. The wise circuit designer learns how to analyze the sensitivities of circuits’ critical characteristics to the variations in the components. With this knowledge, the designer can better decide how to balance any trade offs between performance and cost. Deeper use of sensitivity analysis can lead designers to modify circuit topologies, or make completely different choices in order to optimize these trade offs. Generally, circuit sensitivity analysis is not part of the bachelors curriculum in most universities’ electrical engineering programs. Fortunately, this important topic is easy to learn and use and is covered in circuit design books, especially those focusing on ﬁlter design. A simple, if imprecise, deﬁnition of circuit sensitivity is how much a particular circuit characteristic changes as a particular component value varies. This can be any circuit characteristic: ampliﬁer gain; bus receiver input impedance; an RF port’s voltage standing wave ratio; or a digital gate threshold voltage. In this article, we use analog ﬁlters to explore sensitivity analysis as this information is often critical to good ﬁlter design. We will see that it is fairly easy to extend sensitivity analysis to other types of circuits. A 30 MAY 2008 | embedded systems design europe | www.embedded.com/europe http://www.embedded.com/europe

Table of Contents Feed for the Digital Edition of Embedded Systems Design Europe - May 2008

Embedded Systems Design Europe - May 2008 Contents Microsoft Provides Embedded Roadmap Enea Buys Developers Irish Start-Up Raises Funds for Telecom FPGAs Kontron Promotes COM Express Nano Mentor Nucleus Platform Provides UI for Atmel Small Form Factor Boards Head for the SUMIT Proffibus Advances IO-Link Integration Embedded Developers Cautious on Multicore Auto Cooperation Improves Test Altera Launches DO-254 Partner Network Building an ‘Instant-Up’ Real-Time Operating Systems An Architecture for Reusable Embedded Systems Software Free up Bandwidth in PCI Express Evaluating Software in Medical Devices Circuit Sensitivity in Analog Circuits Choosing Flash Memory New Products Advertising Contacts

Embedded Systems Design Europe - May 2008

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