Timeline for Fully differential opamp with weird behavior
Current License: CC BY-SA 3.0
23 events
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| Oct 6, 2017 at 0:02 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
| Sep 4, 2017 at 4:09 | history | tweeted | twitter.com/StackElectronix/status/904556928256368640 | ||
| Sep 3, 2017 at 23:16 | history | bumped | CommunityBot | This question has answers that may be good or bad; the system has marked it active so that they can be reviewed. | |
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| Jan 17, 2017 at 19:22 | comment | added | D.A.S. | @Yatekii You can see the % distortion by the asymmetry of the sine +pk and -pk % difference. | |
| Jan 16, 2017 at 16:12 | comment | added | D.A.S. | @Yatekii The VNA sees 28 Ω//(237+250)Ω =22.8 Ω not 50 Ω . Probe the output under this load for distortion not just with a 50 Ω termination your termination is 250 Ω on the unmonitored side and DUT to VNA while DUT output load is 237+28//50 Ω =255 Ω | |
| Jan 16, 2017 at 11:36 | answer | added | Andy aka | timeline score: 1 | |
| Jan 16, 2017 at 7:43 | history | edited | Yatekii | CC BY-SA 3.0 |
Changed sweep range from 30 to 50 MHz.
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| Jan 16, 2017 at 7:39 | comment | added | Yatekii | I do not overload the amp, if you mean that. I can see the picture perfect sinewave that i feed in come out again at the oscilloscope if I terminate it with 50 Ohms. | |
| Jan 16, 2017 at 7:27 | comment | added | Yatekii | @TonyStewart.EEsince'75 how do you mean mismatched? Like that the amp sees 250 Ohms and the VNA sees 50 Ohms, so everything sees what it expects.Well I actually did not verify there is no THD, I just assumed it since through all frequencies the amplification is constant +- statistical error. Well about compression: I mean isn't that one effect that could be responsibe for my plots? So idk but isn't that exactly what I asked about? :S Or are you talking about the AD8331 measurements? | |
| Jan 16, 2017 at 7:19 | comment | added | Yatekii | @WhatRoughBeast Uhm of course it should be 50 MHz ... | |
| Jan 16, 2017 at 3:43 | comment | added | D.A.S. | How did you manage to come up with this impedance mismatched R network? How did you confirm there is no THD or compression in your results that could result in false fundamental s21 response. | |
| Jan 16, 2017 at 2:38 | comment | added | WhatRoughBeast | "I sweep only up until 30MHz" - So why do your plots go to 50 MHz? | |
| Jan 15, 2017 at 22:04 | comment | added | Yatekii | I added the missing information and hope I didn't miss something again ... :) | |
| Jan 15, 2017 at 22:02 | history | edited | Yatekii | CC BY-SA 3.0 |
added missing information on how DUT is tested
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| Jan 15, 2017 at 21:31 | comment | added | Bimpelrekkie | Seems you have some 1st order cut-off behavior. I see two RC networks at the output which could be responsible for this. I would also need to know all details of how you apply the input signal and measure at the output. Your VNA probably has 50 ohms inputs ? | |
| Jan 15, 2017 at 21:27 | history | edited | Bimpelrekkie | CC BY-SA 3.0 |
added 38 characters in body
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| Jan 15, 2017 at 21:22 | history | asked | Yatekii | CC BY-SA 3.0 |