OP-AMP Design Problem?

Question

Using only two op-amps with the following specs:
1: Low Frequency Gain: 2e5 V/V
Unity Gain Frequency: 1.5 MHz
Slew Rate (Rload less than 1k ohms) = .7 V/us
2: LFG: 15e5 UGF: 8MHz SR(load less than .5k): 2.8 V/us

An amplifier must be built with a gain of 100 V/V, a max output voltage of 4 Vpp and a bandwidth of greater than 130 kHz

How would I go about starting to construct this....any pointers?

Answer 1

This is not an op-amp design problem, its a design problem that would take quite a few calculations. First though you have to decide upon a suitable circuit for you application, you have all the data, log-on to the manufacturers website and there are a host of example circuits, though you will have to do the calculations yourself to customize the circuit to your specifications. Again all the formulas are there too. Just build one to the closest specifications and adjust it accordingly.

Answer 2

Hmm.. are those the only 3 design requirements? And do you have to use both?

Most op-amps can give you that gain ratio and that bandwidth(looks like the 2 above will, just make sure you don't use any capacitors or inductors in your overall circuit). I would just use a simple inverting input configuration setting r2/r1 to 100, and
then make sure I'm using an op-amp that can be powered with as little as a +/- 4V supply(sneaky idea!).This way, the output can't possibly go higher than +/-4 volts.But check with your professor first to see if that would be kosher. I wouldn't even use two op-amps.

But what about the slew rate? do you have a design requirement for that? One thing you could do is to take, say, a 100 ohm resistor and connect it between your output and ground. Then, if your op-amp output were to go to a high resistance Rload, the Rload would be in parallel with the 100 ohms, effectively keeping your equivalent Rload very low. The 100 ohm resistor will essentially HOLD your output resistance below 1000 ohms(say for op-amp#1)
no matter what you connect it to, which will keep your slew rate the same.

Last but not least, if you really want to go for the gusto, do a 2 op-amp configuration, each one a simple inverting input stage, give each stage a huge r2/r1 ratio, power each with just +/- 4 volts, use the output 100 ohm resistor, and TIE the Final Output back into the initial input, and you'll get a HUGE gain-bandwidth product!. BUT... you'll probably also make the circuit unstable too. Unless you know how to do stability analysis. But hell, hook it up, and see if it goes haywire. Good luck!

Answer 3

that's been a whilst on condition that I did any of this, yet i'm exceptionally specific which you won't be able to get 2 diverse advantageous properties on 2 inputs to the comparable op-amp. you will ought to apply dissimilar op-amps, one in all each and every configuration you suggested seems perfect. I undergo in concepts that the non-inverting had a dilemma (earnings won't be able to be under a million, perhaps?)