Op-Amp vs instrumentation amplifier in signal conditioning application

[Ahmad Tarek]

Hello everyone,
I have a questions and i hope someone can help me with,

I am currently working on a medical device comprising 8 analog sensors, i use low pass active filter as an analog signal conditioning.
Some sensors require output amplification as their output is within the range(0..100mV).
I am currently using LM324 for active filter and amplification application, which is very cost efficient, however, i have been advised to use instrumentation amplifier instead,
The problem with the instrumentation amplifier is that they are really expensive,

Can someone please advise and explain which type of amplifier should i use and Why?

Thanks in advance,
Ahmad Tarek

 

[GregLocock]

I suggest you ask the person who asked you to change why they did so. Also, presumably, you have some sort of spec. Does the current system meet this spec?

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[IRstuff]

Without knowing your design requirements, how are we supposed to evaluate the merits of your design?

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[MacGyverS2000]

You can always make an instrumentation amp (to a degree) out of two regular ones, if the cost difference is significant enough...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Comcokid]

If the sensors are strain gauges or unconditioned pressure sensors then a instrumentation amplifier is the way to go. These require differential input amplification also.

But if these 'sensors' have internal active circuits and a single-ended output then a regular op-amp may be the better way to go.

I've designed many sensor and control circuits for -40 to 85C using no more than LM2904 opamps (LM324 family). Not hard to do if you know your signal source and you arrange the circuit so the input bias current/offset voltage will cancel in the circuit. I've also designed circuits where I never considered anything other than instrumentation op amp from the start.

 

[Ahmad Tarek]

Thank you everyone for your answers,
I am attaching the circuits where i am using the op-amp,
Filtering circuit

Amplification circuit

Thanks in advance