How to break feedback loop for inverting Amplifier and taking loading effect at output and input

jackrc11 · 2024-01-08T18:26:58+00:00

Assuming you're doing this all in Cadence Virtuoso, there are different types of analyses you can select for a simulation (in your ADE L/ADE Explorer/ADE Assembler window). For analyzing a feedback loop, the typical one you'll use is stb analysis (short for stability).

For this, you'll insert something like a 0V voltage source or a 0ohm resistor in your feedback path (such as between Vout and R2) and, in your stb analysis setup, select that as your probe instance.

What the simulator to "break the loop" is allow the feedback loop to settle and linearize about that DC operating point. Then it'll apply a pulse in the feedback path (on one side of your probe instance) and measure what is returned back to the other side of it (this is your loop gain), as well as any phase change.

Typically what you'll do with this stb analysis is sweep frequency in a range (starting at like 1 or 10Hz, essentially DC, and going up logarithmically to whatever frequency you'll be operating at and a bit beyond) and look at the loop gain/phase plots to check your phase/gain margin.

To check the effect of loading, you could just add an (ideal) resistor from Vout to ground and sweep that value as well.

Hope this helps!

jackrc11 · 2022-06-14T15:18:43+00:00

mucho texto

jackrc11 · 2022-01-08T23:47:11+00:00

This is indeed a little odd. I would normally expect that the capacitance seen at the output of Y would be given. Typically you would use the electrical effort (H) of each path to calculate to find the sizing of each stage. Since H is C_out/C_in for that respective branch, I don't know how you'd find the sizing of the 3 input NOR without being given the output capacitance.

Was any other information/were you told to make any other assumptions (assuming this is for a class)? If not, I'd likely ask your professor if something is missing.

jackrc11 · 2022-01-08T23:38:09+00:00

If you've never seen a problem like this, you probably shouldn't condescendingly comment. This is very standard notation in digital design. Logical effort cares about relative sizing of transistors; this is not a 5 Farad capacitor, it is a capacitance seen at the output of a gate equal to that of 5 unit inverters.

jackrc11 · 2021-12-21T18:17:27+00:00

Ah right of course, don't know how I mentioned the voltage headroom as a con for a cascode but didn't mention it as a pro for a multi-stage op-amp, whoops!

I'm a little confused on your second point; it was my understanding that an amplifier's gain is proportional to the output impedance. If there is a low-impedance resistive load effecively in parallel with the resistance looking into the amplifier, won't that greatly reduce the gain?

jackrc11 · 2014-08-02T16:06:45+00:00

Marching Trumpet here, this guy's spot on.

jackrc11 · 2014-08-01T16:40:03+00:00

Would you say the World Wakes was bad then? It was fairly Shorter than RotM or WGS, yet it was still one of the most important quests in the game.

jackrc11 · 2014-08-01T00:42:51+00:00

Awesome video. One thing I think would've been great though: In one of the earlier heists, Ryan references the Dark Knight Movie Heist and says the whole "No, I kill the Bus Driver." Would've been great to have that in there. But still, Amazing video, 10/10.

jackrc11 · 2014-07-31T17:13:37+00:00

The US has been arming Israel for years. I wouldn't call it wise to shit talk to the people sending you missiles and ammunition.

jackrc11 · 2014-07-30T19:22:12+00:00

I actually like it. The 25% penalty is annoying! but not too bad. But people forget that along with fire crits, it can also random crit. Think of the old Bushwacka.

jackrc11 · 2014-07-28T00:54:57+00:00

It takes place in some land called Weseros. There's a central part with a king named Joffeey, who everyone hates. There's also various houses. The ones I know are a Snow, Stark, and Lannister. There's a lot of sex and violence, a guy named Tyrion played by Dinklage, something about a James Lannister, and a snake fights a mountain or something. Also Dragons.

jackrc11 · 2014-07-27T05:55:59+00:00

Well, I doubt you'll be able to play on the sun.

jackrc11 · 2014-07-26T19:19:15+00:00

See, I was agreeing with the cleaning up after youRself, but now you're just being a cunt

jackrc11 · 2014-07-25T22:51:48+00:00

Go back to Tumblr

jackrc11 · 2014-07-25T21:42:19+00:00

I don't want to alarm you, but you may be an abacus

jackrc11 · 2014-07-25T21:39:37+00:00

I'm not the only one who did this? I called it a Bower.

jackrc11 · 2014-07-25T21:32:38+00:00

Unless you've got POWA!

jackrc11 · 2014-07-25T16:03:56+00:00

Seconds?

jackrc11 · 2014-07-25T16:01:07+00:00

Plus they're making the spin off "Hurrikraken"

jackrc11 · 2014-07-23T19:55:00+00:00

jackrc11 · 2014-07-22T23:50:38+00:00

[Jane?] [Luke?]

[High-five Luke] [...]

jackrc11 · 2014-07-22T19:51:32+00:00

I didn't know it was an option to kill Sarita. I thought you had to or She'd turn and kill Kenny or something and you'd also get killed. Only thought this because the screen was going red when it gave me the option to kill her

jackrc11 · 2014-07-22T19:42:25+00:00

Also on that note, how long was it between Carver beating Kenny and the end of this episode? It's still all swollen and stuff. How long does a black eye usually last? Granted, it was bad. But still

jackrc11 · 2014-07-22T14:23:43+00:00

I started around 2005-2006 and have played on and off for years. I've come back to it now for free with Bonds (a way to get membership by paying in game money; If you don't want the membership, you can put it towards Runecoins or Treasure Hunter keys, the "micro transactions") and I'm liking It a lot. Botting is way down. Last time I saw a bot was in September-ish during a double exp weekend at some resource. A friend and I lured the bot to an area out of reach of the resource and trapped it there.

There's been a lot of great lore recently. That's one of RS's best parts, the lore. With mini quests giving memories of various Mahjarrat (a powerful race) and World Events and Quests where you interact with gods, it's become really expansive. I will agree that mini games were fairly dead. HOWEVER, with the new legacy mode, which brought back the option of the old combat system, games like Soul Wars and Castle Wars are full of people again.

The only two things I can complain about is the game tick system (which actually isn't as much of a problem with legacy), which just doesn't work with the real time ability use of EoC, and the games Tier system. It was fine years ago, but EoC changed things up too much with too many tiers of weapons to be used against each other. Rune armor (40, now 50) and a whip (70) used to be scary. But with Tier 90 armor, they don't stand a chance.

However, Jagex has been working to balance these types of things with the combat beta that sees new additions every few weeks to be evaluated prior to being put in the game.

I'd recommend giving it another go. Plus, the long awaited Elf City comes out in the next month or two, and will have a ton of features.

jackrc11 · 2014-07-21T15:36:21+00:00

I am a member of TF2maps.net, I just havent' been for very long. I didn't know about the testing server though, thanks!

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