Hi, I have similar requirement to get 30Vpp sine wave, but higher frequency up ranging from 50kHz to 350kHz, does the circuit in #7 work for the requirements? thanks in advance for your kind help.

MOD NOTE: Thread was split off from another similar thread.

https://forum.allaboutcircuits.com/threads/sine-wave-amplifier-circuit-using-op-amp.108387/#post-1170783

 

Hi, I have similar requirement to get 30Vpp sine wave, but higher frequency up ranging from 50kHz to 350kHz, does the circuit in #7 work for the requirements?

The original requirement was for a 4 kHz bandwidth. Your signal bandwidth is 88 times greater. This will require a significantly faster opamp. Since you know the gain and bandwidth you need, you can calculate the gain-bandwidth product (GBW) and compare it to datasheets. As a starting point rule of thumb, you want an opamp with at least 10 times more GBW than you need.

ak

 

Thanks ak. I had searched for a fast op and found LM7171, which unity gain bandwidth is 200MHz, slew rate is 4100v/us at the conditions when Vin 13v and Av is +2. Per the characteristics graphs, gain is around 30dB~45dB at 1M~10MHz, GBW at Vs=+/-15v is 200MHz. These look promising. Do you think this op can fit to my purpose?

PS: just noticed the system split off a new thread for this topic. I copied my reply from the original thread.

 

Also I dont think you will you get more than "12V" from this opamp, you will need to amplify it to "30V" somehow.

 

Hello,

Looking at the datasheet, with a powersupply of ± 15 Volts, you will get 26 Vpp max as output with an 1K load.
With a lower load you will even get less output.

Bertus

 

I would say "24V" "2x12v" with a dual power supply. The datasheet is not always perfect, normally those are ideal parameters, which is good but we still need to know the practicle value.

 

Thanks ak. I had searched for a fast op and found LM7171, which unity gain bandwidth is 200MHz, slew rate is 4100v/us at the conditions when Vin 13v and Av is +2. Per the characteristics graphs, gain is around 30dB~45dB at 1M~10MHz, GBW at Vs=+/-15v is 200MHz. These look promising. Do you think this op can fit to my purpose?

PS: just noticed the system split off a new thread for this topic. I copied my reply from the original thread.

Hi,

Did you state what your input voltage was? You need to consider that vs the output voltage.
That chip has very high speed but it's good to look at this just to make sure.

 

Thank you all for your inputs. The input voltage is 1Vpp from a function generator. Before I will purchase lt7171, I tried yesterday on-hand slow op lm741 at 1kHz. It can amplify 1Vpp to 30Vpp without problem. Of course it is not fast enough for me. Besides lt7171, is there any other fast op amp proven fitting to my requirements (to amplify 1Vpp sine wave to 30Vpp, frequency 50k~300kHz, better 350kHz if possible)? Thanks.