Analog differential driver

Hi there - I am looking for a good way to drive a board that takes a differential analog -10-10V signal. I am using a current output DAC. My current plan is to run the current output DAC through a simple transimpedance amp (ie

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and then pipe that into a op-amp difference amplifier. That'll give me one side, but how do I invert it? Sure, I could use an inverting amplifier with a gain of 1, but that'd give me a delay between transitions, which I would ideally like to avoid. Are there any good ways to handle this situation? Maybe is there such thing as an analog differential driver chip? When I search for such a beast, I just get diff drivers at made by Analog. When I get rid of the Analog results I can't seem to find anything. I can't imagine this is *that* uncommon of a problem. Suggestions? Argh.

-Michael

Reply to
Michael
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Don't google for "analog differential driver", just for "differential driver" or "differential line driver".

There are many differential drivers, from different manufacturers. I can't really pin out just one of them, you'll have to compare datasheets and see which one is good for your circuit. Or, you can build your own differential driver using regular opamps. It's not that complicated.. One opamp does noninverting buffering/amplification for + signal. The other one is connected as inverting opamp, doing the same buffering/amplification for - signal. So, it's symmetrical (enough).

Using reasonably fast opamps, there's no delay that would have any effect. Unless you are using signals which are very fast (like hundreds of MHz).

Reply to
Mika Lindblad

Does the dac have diff current outputs? What's its part number?

How fast does this need to be?

John

Reply to
John Larkin

Right, you just need to *know* how to do it...

Reply to
Fred Bloggs

The standard way of single ended to the differential conversion is using the two identical differential amps. One is inverting the signal, the other is not inverting. This provides for the completely symmetrical configuration. The full differential opamp may be used for that also, however there are not too many opamps of this kind.

You can also find some interesting topologies here:

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Although their configurations are not strictly symmetrical.

Vladimir Vassilevsky

DSP and Mixed Signal Design Consultant

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Reply to
Vladimir Vassilevsky

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