Hi there, noob here, this may be a dumb question, but... I’m working on a small project to capture EMG signals, and I plan to read them using a microcontroller’s ADC. In a very general overview my setup includes an instrumentation amplifier (AD620ANZ) followed by a second-order bandpass filter to capture frequencies from 20 Hz to 500 Hz. However, I need a dual-rail power supply (+5V and -5V or even more) to power my ampOps, the ideal solution would probably be using a dual power supply, which I don't have. After doing some quick research, I found that using a voltage divider and a buffer configuration might be sufficient to generate the dual-rail voltage.
My question is, the buffer output will serve as my new reference ground, but if I want to connect my instrumentation amplifier next, where should I connect the new ground to ensure it becomes the reference ground for the following amplifier stages, I mean how do I get +5V and -5V in respective v+ and v- second stage?

 

Hi Spo,
Please post your LTS asc file.
E

 

Hi Spo,
Please post your LTS asc file.
E

 

Hi S,
I was going to modify/add to your file, is there a problem with that?
E

 

Hi S,
I was going to modify/add to your file, is there a problem with that?
E

There is no problem!

 

Hi S,
Add the 1uF.
My 741 model asy is different from yours, so you will have to draw the lines
E

 

Hi S,
Add the 1uF.
My 741 model asy is different from yours, so you will have to draw the lines
E

So now, we establish a single common GND for both, first and second stages. I truly appreciate your help.

 

Now that the "mid-supply common" voltage is created, what is important will be to keep the negative side of the single voltage supply isolated from the analog circuits. If the single voltage supply is not used for anything else, and it it's negative is not tied to "ground" that should be easy.