suggest me a suitable op-amp

Thread Starter

pratapkollu

Joined Dec 13, 2006
42
respected members
I need an op-amp that is active even after 100KHz(in frequency Vs Vom-maximum peak output voltage graph), I need output voltage between the range of 100 to 200khz. Please see the atached figure. presently i am using TL082, but its inefficient. Please suggest me suitable op-amp(preferably like TL082, same pin configuration). This is because I have already made PCB using TLO82 op-amp.
Thanks and Regards
Pratap

http://i173.photobucket.com/albums/w68/prince_beckham/graph.jpg
 

Papabravo

Joined Feb 24, 2006
12,301
When you say the TL082 is inefficient, what does that mean exactly. Linear circuits, like class A amplifiers, are often inefficient. What supply voltage are you using?
 

bloguetronica

Joined Apr 27, 2007
1,359
There are class AB amplifiers like the TDA2003, but I don't know if it is suitable for you. I'll finish a project using this particular amp soon.
 

nanovate

Joined May 7, 2007
665
input is 0.5V(peak-to-peak) 100 kHz sine wave
and I need 10V(peak-to-peak) 100 kHz sine wave at output
For your circuit you need a gain of 20 at 100KHz so you need an opamp that has plenty of gain left at 100KHz -- I recommend an opamp with 10 MHz GBWP minimum. This would leave plenty of open loop gain. Maybe there is something like the TLC082 from TI. It won't work for your design-- close but it is single ended with max supply of only 16V. I will take a look around though and maybe I can find one that'll work. It has become harder to find fast opamps that are "high" voltage and are in DIP.


The TL082 is a dual opamp, are you using both?


presently i am using TL082, but its inefficient
I am not sure what you mean by that. Are you referring to the fact that it is not a R-R output and so you need to use +/-15V supply to get a +/-12V swing? Or do you mean that it has a high power consumption?
 

Distort10n

Joined Dec 25, 2006
429
Simply picking an amplifier with 10 MHz GBWP will not help. It is not just a function of gain bandwidth, but also slew rate. Case and point, the OPA228; it has 33 MHz of GBW. If his input peak voltage was 500mV, then he would expect slew rate induced distortion roughly around 160 kHz.

FPBW (full power bandwidth) is a function of slew rate, signal gain, and input peak voltage:

FPBW = SR/(2*pi*Av*Vpeak-in)

The OPA2228 should work since his peak input voltage is only 250mV. That should give him roughly 320 kHz of bandwidth. It will also serve a 20Vp-p output swing on a +/-15V supply, assuming no load conditions.
 
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