Fully Differential Summing amplifier

Kyle Aven

Intellectual 950 points

Other Parts Discussed in Thread: LME49724

Is there a way to create a fully differential summing amplifier? Internet searching has not produced any results.

thanks

over 12 years ago

0 Matt Lauer over 12 years ago

TI__Expert 7925 points

Hi, Kyle. Is the setup in this article not what you are looking for? http://masteringelectronicsdesign.com/a-summing-and-differential-amplifier-with-one-op-amp/

We offer an Application Report of a collection of differential op-amp circuits. It doesn't have the exact terminology you're using, but it may give you some ideas. There might be a way to implement your desired circuit in there! http://www.ti.com/lit/an/sloa064/sloa064.pdf

I've asked my colleague John to chime in on this.

Best Regards,
Matt

0 Kyle Aven over 12 years ago in reply to Matt Lauer

Intellectual 950 points

Matt,

i saw that article but it doesnt address what im trying to accomplish. I guess to be more specific, i woul like to use a single fully differential op amp to sum two signals and perform single-to-diff conversion all in one stage

0 John De Celles over 12 years ago in reply to Kyle Aven

TI__Expert 3840 points

Hi Kyle,

It sounds like your sources single-ended?

Is there a particular reason you want to use a fully differential in/out IC?

I think you could use the circuit shown in Figure 19 of SLOA098 and just add a second summing resistor as Matt has shown and accomplish the task with one dual op amp in a single package. Would that work?

Best Regards,

http://www.ti.com/lit/an/sloa098/sloa098.pdf

0 Kyle Aven over 12 years ago in reply to John De Celles

Intellectual 950 points

we are currently using multiple single-ended output op amps. i was just trying to cut down on part count and board size. If the signal summing, differential conversion, and output bias could all be done in one op amp that would be a huge help. what i am asking may not be possible. just thought i would ask to be sure

0 John De Celles over 12 years ago in reply to Kyle Aven

TI__Expert 3840 points

Hi Kyle,

I'm not sure if all diff-in/diff-out are internally configured to allow for this, but it looks like this part (LME49724) may work. Check out Figure 3 in the datasheet on page 14.

Best Regards,

http://www.ti.com/product/lme49724

0 Alec Schmidt over 8 years ago

Prodigy 60 points

I realize I'm responding to an almost five year old post, but since I had what I believe is the same question and I found an answer (although an unfortunate one)... for the sake of any others who find their way here.

lushprojects.com/.../

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Fully Differential Summing amplifier