Avoiding Performance Pitfalls for the Pulse Response of High-Speed Op Amps: Part 1
Where the various estimates of rise time, slew rate, and full power bandwidth come from and why they might be misleading
by Michael Steffes
Any designer setting out to apply a high-speed amplifier to a time domain type application (as opposed to frequency domain) will need to consider the critical specifications associated with the pulse response for that amplifier. Most supplier data sheets do a good job of showing what a designer might expect under the limited set of conditions used to specify the amplifier. Occasionally, somewhat misleading data is shown in the data sheets or slight misconceptions that have crept into the industry confuse the issues surrounding the expected pulse response.
This series of 4 articles will first step through the basics showing where and why some of the inconsistencies have crept into the specifications, move on to a more detailed mapping of small-signal frequency response to pulse response along with a slew rate discussion for both voltage feedback (VFB) and current feedback (CFB) op amps, consider what changes can be expected in the pulse response vs. external circuit conditions along with some test and measurement issues, and conclude with a survey of where the most recent products are heading and some external tricks available to improve the pulse response.
...download complete article here (370 KB PDF)
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