PreAmp designing-Please help

Thread Starter

Michael1989

Joined Feb 14, 2012
4
Hello,

So i need to design and make a pre- amplifier with the following specifications.
Runs on a 3.3-5 volt supply
Gain levels from 10-50dB
Must function from 5-50kHz
Low noise levels

I was wondering if anyone had any ideas of were i should start below are some of the calculations that i have done to help me select my opamps.

50dB=316.23V/V
316.23V/V x 50KHz=15.8 MHz
Now that my signal will also be filtered i know that i will need to raise it to probably around 100KHz accepted by my filter.

Thought about using an AD8099
Has a small signal bandwidth of 500MHz -Slew Rate 1.6KV/us -Vos of 200uV Noise Density of 950pV/rtHz and fits my voltage level limits

Wondering if anyone knows of how i should go about this project and picking resister and capacitor values.
 

Thread Starter

Michael1989

Joined Feb 14, 2012
4
Hello,

You could also take a look at this opamp:
http://www.national.com/pf/LM/LMH6629.html#Overview

Are you allowed to use two stages?
Then you can use simpler opamps with less bandwidth.

Bertus
Thank you for the response so quickly. I think i am allowed two stages. To my memory i forget the downsides or upsides to using a two stages. I have also attached a beginning design i have come up with not sure how to actually figure out the values.
 

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