|
|
|
|
|
||||||||||||||||||||||||||||||||||
| Specifications | Are wide bandwidth and fast slew rate the best way to benchmark an amplifier? Rarely Asked Questions \Beware of big claims and large numbers.they don t always add up.\ Rarely Asked Questions, RAQs, amplifier, John Ardizzoni, slew rate Analog Devices |
| Business section |
| Specifications | Are wide bandwidth and fast slew rate the best way to benchmark an amplifier? Rarely Asked Questions \Beware of big claims and large numbers.they don t always add up.\ Rarely Asked Questions, RAQs, amplifier, John Ardizzoni, slew rate Analog Devices |
| Suggested Link Details/Purchase | |
| Content | RAQ’s SPECIAL ADVERTISING SECTION Strange stories from the call logs of Analog Devices SPONSORED BY Have a question involving a perplex- ing or unusual analog problem? Submit your question to: www.analog.com/ askjohn For Analog Devices’ Technical Support, Call 800-AnalogD To Learn More About Specifying Op Amps http://dn.hotims.com/40992-1000 A: Not necessarily; op amps typically specify 30 or more individual parameters. The task you’re trying to accomplish will dictate which of these specifications are most important to you (and your circuit). When evaluating amplifiers, or any component, it is important to make sure you understand the specifications, the test conditions, how test data is collected, and how it is presented, as different manufacturers sometimes present the same parameters in different ways. Knowing both the test conditions and your circuit needs is imperative when comparing parts. Since you brought up bandwidth and slew rate, let’s have a look at those specifications. Some people think, “the larger the bandwidth, the better,” but the savvy analog engineer knows that having just enough bandwidth is better than having hugely excessive bandwidth. The best way to evaluate any parameter is to read the data sheet and look at the plots, as they tell the real story of how the amplifier will behave. Is there excess peaking in the bandwidth plot? Some manufacturers will spin this as a larger –3-dB bandwidth, but it may also indicate that the part has stability issues. Even though the –3-dB bandwidth may appear large, the amplifier’s gain flatness may be decreased because of the peaking. Therefore, address bandwidth on just how much you need, noting that wider bandwidth amplifiers require more attention to stability and PCB layout. Slew rate (SR) is the rate of change at an amplifier output due to a sudden change at the amplifier input. It is typically measured in volts per microsecond (V/μs). The maximum large-signal operating frequency can be determined by using the equation F=SR/(2πVp), where Vp is the peak voltage. Some amplifiers feature very large slew rates, trying to wow engineers with large numbers, but they are not always needed, because the maximum operating frequency will be limited by distortion. The easiest way to check this is to look at the distortion plots for your frequency of interest. Is the distortion level acceptable for your application? Again, knowing your system requirements is paramount. Then, plug this frequency into the slew rate equation and see exactly how much slew rate is needed. In some cases, big numbers don’t add up to better performance. Know your circuit and what you need to get the job done. Add a little more for margin and look at the plots… they tell the real story. Beware of big claims and large numbers… they don’t always add up Contributing Writer John Ardizzoni is a Technical Product Manager at Analog Devices in the High Speed Linear group. John joined Analog Devices in 2002, he received his BSEE from Merrimack Col- lege in N. Andover, MA and has over 30 years experience in the electronics industry. Q: Are wide bandwidth and fast slew rate the best way to benchmark an amplifier? |
| Suggested Link Details/Purchase | |
| Following Datasheets | RAQ_AmplifierHeadroom_1 (1 pages) RAQ_amplitude_1 (1 pages) RAQ_analogDigital_1 (1 pages) RAQ_analogICs_1 (1 pages) RAQ_Ancient_Logic (1 pages) RAQ_attenuator_1 (1 pages) RAQ_balancing_Phase (1 pages) RAQ_biasCurrent (1 pages) RAQ_Burning_Cakes (1 pages) RAQ_capaciticectomy (1 pages) |
Check in e-portals |
World-H-News Products Extensions Partners Automation Jet Parts |
| Sitemap Folder | group1 group2 group3 group4 group5 group6 group7 group8 group9 group10 group11 group12 group13 group14 group15 group16 group17 group18 group19 group20 group21 group22 group23 group24 group25 group26 group27 group28 group29 group30 group31 group32 group33 group34 group35 group36 group37 group38 group39 group40 group41 group42 group43 group44 group45 group46 group47 group48 group49 group50 group51 group52 group53 group54 group55 group56 group57 group58 group59 group60 group61 group62 group63 group64 group65 group66 group67 group68 group69 group70 group71 group72 group73 group74 group75 group76 group77 group78 group79 group80 group81 group82 group83 group84 group85 group86 group87 group88 group89 group90 group91 group92 group93 group94 group95 group96 group97 group98 group99 group100 Prewious Folder Next Folder |
